| ||
| ||
ITEM | DETAILS | |
AUTHOR | Russell Jay Hendel | |
AFFILIATION | Towson University, Towon, Md 21252 | |
TITLE | CONVERTING LECTURE PREPS TO POLISHED WEB | |
PRESENTED AT | ICTCM 15, 11-1-02, 10:20-10:35 | |
ICTCM-15 SECTION | INTERNET / DISTANCE LEARNING TECHNOLOGIES | |
EMAIL ADDRESS #1 | RJHendel@Juno.Com | |
EMAIL ADDRESS #2 | RHendel@Towson.Edu | |
ICTCM-15 CODE | Fri-C1A |
| ||
The GOAL of this presentation is to enable instructors to produce, without extra-time-resources, a web-based-course supplement that has... | ||
ITEM | DETAILS | |
A Syllabus | A traditional 12-15 week syllabus with | |
(Sub)Topics | Indication of Major and minor syllabus topics and | |
Slides | A fully developed set of slides for the course |
| ||
This presentation is targeted to the following AUDIENCE Instructors with the characteristics below can benefit from the ideas presented here*1. We assume that the instructor is... | ||
ITEMS | DETAILS | |
TEACHING COURSES | ||
...using syllabii | The syllabus has about a dozen major course topics | |
--------- | ------------------------------------ | |
MAKING PREPARATIONS | ||
...with Problems | The instuctor already prepares class & HW problems | |
...New concepts | The instructor prepares points introducing new ideas | |
------------- | ---------------------------------------- | |
MAKING USEFUL POINTS | ||
For example, | The instructor points out useful CONTRASTS | |
For example, | The instructor points out useful ANALOGIES | |
For example, | The instructor points out useful OVERVIEWS | |
For example, | The instructor points out useful DISTINCTIONS | |
|
||
*1 To recap, the goal of this presentation is to show how to convert this type of lecture preps to a web-based-course- resource without requiring extra time. |
| ||
The 2 key points in quickly converting lecture-preps to web slides are using a special... | ||
ITEMS | DETAILS | |
TABLE FORMAT | This TABLE FORMAT is discussed in detail below*1 | |
PERL SCRIPT | A Perl script converts the text file to slides*2 | |
|
||
*1 The instructor must write out the lecture preps, that (s)he is already making, in a special TABLE FORMAT. This TABLE FORMAT is discussed in detail below The instructor must write out his/her lecture preps electronically Acclimating oneself to writing in this format isn-t difficult The TABLE FORMAT is flexible and allows up to 6 table features *2 The instructor then uses a perl script or visual basic script to convert the electronic TABLE FORMATS to color coded slides*10 | ||
|
||
*10 Since the perl or visual basic script executes instantly and since usage of the TABLE FORMAT requires no extra time requirements on the instructor it is immediately seen that the above setup enables conversion of the lecture preps to a collection of HTML slides. |
| ||
I first experimented with this idea in 1995 when I was visiting the University of Louisville. While teaching a routine Calculus I course, using Anton, I found I could type my lecture preps in e-text files about as fast as I could scribble them on paper. However the e-text files could be emailed to my students. Student feedback was positive Here are some of the positive aspects of using e-text preps: | ||
ADVANTAGE | DETAILS | |
More time | Students spend more time listening vs writing | |
Absences | E-files are invaluable when a student misses a class | |
NoteTaking | Students print out e-notes & add their own comments |
| ||
I began actively re-experimenting with this setup when I began lecturing at Towson University (1999) which encourages web-based-course material. During this period I have developed the following items: | ||
ITEM | WHAT WAS ACCOMPLISHED | |
Table Format | I developed a TABLE FORMAT with up to 6 features | |
Perl Scripts | I-ve written vb scripts which convert txt to html | |
8 Slide types | The rest of the paper presents these slide types | |
| ||
We can distinguish different types of slides based on the FUNCTION and purpose of the slide. We have identified 8 distinct slide FUNCTIONS. These 8 slide types are listed below and will be discussed in the remainder of the paper This presentation was, in particular, based on material developed for an introductory Statistics course, taught at Towson University in Fall 2002. The URL is contained in footnote *1 Here are the 8 slide types and their FUNCTIONS | ||
TYPE OF SLIDE | Brief description of the slides FUNCTION | |
DISTINCTION slides | Distinguish between TWO similar items | |
DICTIONARY slides | eg Map VERBAL concepts to ARITHMETIC formulae | |
LIST-CONTRAST slides | LIST all possible techniques;hilight CONTRASTS | |
OVERVIEW SLIDES | Revu several course topics with similar methods | |
CONCEPT slides | Introduce a new course-concept | |
HW slides | Revu HW problems: Emphasize KEY points | |
PROCEDURE slides | Problems whose solution requires MANY STEPS | |
SPREADSHEET slides | Problems which are best solved using SPREADSHEETS | |
|
||
*1 The URL is http://www.Towson.edu/~rhendel/m231-f02.htm This URL contains complete information on the course including the name of the text, syllabus, and linked slides. However, this presentation is self contained and understandable without reference to this site. |
| |||
The course used for illustration is a traditional introductory stat course with 3 main COMPONENTS: - Descriptive Statistics, - Distributions, - Sampling inferences & Linear regression. The syllabus is divided into - 3 COMPONENTS*1, - 12 TOPICS*2, - A variety of SUBTOPICS*3, - Several SLIDES on each SUBTOPIC. The table below summarizes this terminology | |||
EACH | IS DIVIDED INTO | FOR EXAMPLE | |
SYLLABUS | 3 COMPONENTS*1 | DISTRIBUTIONS | |
COMPONENT | Topics*2 | BINOMIAL, NORMAL*4 | |
TOPIC | SUBTOPICS*3 | Exp,Variance,Word problems...*5 | |
SUBTOPIC | Slides | The 8 slide type examples given below | |
|
|||
*1 COMPONENTS correspond to exam units *2 TOPICS correspond to chapters *3 Subtopics correspond to chapter subsections *4 That is: BINOMIAL, NORMAL are TOPICS belonging to the DISTRIBUTION component. In most texts there are separate chapters to the BINOMIAL AND NORMAL distributions. *5 The BINOMIAL TOPIC (Chapter) has SUBTOPICS of - Expectation - Variance - Word problems etc Each of these subtopics corresponds to a subsection |
| |||||
At the beginning of the semester I create a 5 column Syllabus The syllabus column headings are -- DATE, -- CHAPTER, -- TOPIC, -- SUBTOPICS, -- SLIDES - Each subtopic is listed on a separate line. - The slides corresponding to each topic are listed on the same line. - Here is a sample syllabus segment | |||||
DATE | Chapter | TOPIC | SUBTOPICS | SLIDES*1 | |
10/3/02 | 6 | Binomial | Discrete RV | 71 | |
10/3/02 | 6 | Binomial | Exp-Var | 72,73,74 75 | |
10/8/02 | 6 | Binomial | Bin Dist | 76,77 | |
10/10/02 | 6 | Binomial | Word problems | 78,79,80,81,82 | |
|
|||||
*1 - The numbered slides are hyperlinked to actual slides. - Each slide corresponds to 1 html page - Each slide performs one of the 8 slide FUNCTIONS developed in the remainder of this paper The above is the main web design. Various other links are added as needed and desired. For example - a COURSE-INFO page or - a PROBLEMS-DONE page listing problems reviewed in class |
| ||
The rest of this presentation will present... | ||
ITEM | SECTION IN PAPER | |
... the anatomy of a slide | Section VIII | |
... the 8 slide types with examples | Section IX | |
... An extended example | Section X | |
... summary and future developments | Section XI |
| |||
The slide after this one reproduces an actual course slide*1 This slide was part of a lecture on basic descriptive statistics. The purpose of this slide is to MOTIVATE the need for VARIANCE besides AVERAGE as a basic descriptive statistic. This slide below has 4 sections:*3 *10 | |||
# | SLIDE COMPONENT | COMPONENT CONTENT | |
VIIIa) | THE SLIDE TITLE: | Avg vs DISPERSION | |
VIIIb) | THE SLIDE DESCRIPTION: | Why isnt average enough? etc | |
VIIIc) | THE TABLE FIELDS: | DATA, AVG, DISPERSION | |
VIIId) | THE TABLE DATA: | eg Temperature data:60 70... | |
VIIId) | THE NOTE SECTION: | Notes are indicated by asterisks followed by # (*3) | |
VIIId) | THE LONGER FOOTNOTE SECTION: | Notes are indicated by asterisks followed by # (*3) | |
*1 http://www.towson.edu/~rhendel/math231-f02/slide44.htm *2 The slide makes the point that in the situation of the first row--average temperature of 70 with little variation--you would only eg need to buy one set of clothes while in the situation of the 2nd row---average temperatures of 50 in winter and 90 in summer-- you would need to purchase two sets of clothes. This distinction hilights the need for a measure of DISPERSION besides the traditional AVERAGE measure *3 2 further slide components allowing explanatory footnotes (or longer footnotes) are not illustrated in the slide below as these features arent traditionally used in every slide | |||
|
|||
*10 Again: A fundamental assumption of this presentation is that an instructor could acclimate him/her-self to preparing this slide electronically on say notepad in about the same time that they could prepare such a slide on pencil and paper. |
| |||
Why isnt average enough? Why do we need a second measure? The example below illustrates | |||
TEMPERATURE DATA | AVG | DISPERSION | |
60 70 70 70 80 | 70 | Buy clothes for 70 weather | |
40 50 60 80 90 100 | 70 | Need 2 sets of clothes |
| ||
In this section we present the 8 slide types. Each slide type corresponds to a distinct slide FUNCTION Each slide is preceded by a slide describing - the URL for the reproduced slide - the FUNCTION of the slide - Key points & CONTENT of the slide The first slide type is the DISTINCTION SLIDE | ||
ITEM | DETAILS | |
url | http://www.towson.edu/~rhendel/math231-f02/slide44.htm | |
FUNCTION | Use a punchy distinction to motivate a point | |
CONTENT | Motivate need for a VARIANCE besides AVERAGE |
(C) Dr Hendel, Sep-02 | |||
Why isnt average enough? Why do we need a second measure? The example below illustrates | |||
TEMPERATURE DATA | AVG | DISPERSION | |
60 70 70 70 80 | 70 | By clothes for 70 weather | |
40 50 60 80 90 100 | 70 | Need 2 sets of clothes |
| ||
In this section we present the 8 slide types. Each slide type corresponds to a distinct slide FUNCTION Each slide is preceded by a slide describing - the url for the reproduced slide - the FUNCTION of the slide - Key points & CONTENT of the slide The 2nd slide type is the DICTIONARY SLIDE | ||
ITEM | DETAILS | |
url | http://www.towson.edu/~rhendel/math231-f02/slide88.htm | |
FUNCTION | Create a MAPPING of 2 disparate domains(eg Algebra & Geometry) | |
CONTENT | Probability formulae for keywords AT LEAST,AT MOST... |
(C) Dr Hendel, Sep-02 | ||
We redo the word problems for the normal distribution*10 Again we relate KEY PROBLEM WORDS to CUMULATIVE PROBABILITIES*11 (Added 10-29-02 Compare slide79--Binomial word problems) | ||
WORD PROBLEM TYPE | RELATIONSHIP TO CUMULATIVE PROBABILITY | |
AT MOST*1 | P(At most h) = P(H<=h) | |
AT LEAST*2 | P(At least h) = 1-P(H<=h)*3 | |
BETWEEN | P(Between a & b) = P(H<=b)- P(H<=a)*3 | |
EXACT | P(EXACTLY h) = P(H<=h+.5)-P(H<=h-.5)*4 | |
|
||
*1 STUDENT QUESTION (CORRECTED 10-29-02) MORE THAN h is the same, for BINOMIAL, as AT LEAST h+1 MORE THAN h is the same, for NORMAL, as AT LEAST h h or LESS is the same as AT MOST h for BINOMIAL or NORMAL *2 STUDENT QUESTION (CORRECTED 10-29-02) LESS THAN h is the same, for BINOMIAL, as AT MOST h-1 LESS THAN h is the same, for NORMAL, as AT MOST h h or more is the same as AT LEAST h for BINOMIAL or NORMAL *3 In the BINOMIAL word problems we use h-1 and a-1 The minus 1 is not present in the normal problems Also in the normal problems it does not make a big difference if you use the LESS THAN vs LESS THAN OR EQUAL*10 *4 This is called the CONTINUITY correction. It takes a long time till students get this correct. I am therefore not covering it on tests since students expressed a desire for further practice on the other items | ||
|
||
*10 STUDENT QUESTION ---------------- Recall the BINOMIAL RV is DISCRETE (Possible values:0,1,2,.. By contrast the NORMAL RV is CONTINUOUS( eg height=6.1111) In a discrete rv,eg MORE THAN 10 means 11 or more(AT MOST 11) In a continuous rv, MORE THAN 10 means 10 OR MORE The point is that the probability of EXACTLY being 10 feet tall is 0 (eg you might be 10.001 or 9.999) So we - dont have to add the minus 1 - dont have to worry about less than or equals Nevertheless purists can use or omit the equality sign *11 STUDENT QUESTION ---------------- This table is not in the book. But it is not something to MEMORIZE rather it is something to UNDERSTAND. All the slides are logical. For example to analyze -- MORE THAN 11 -- we ask if 10 is an example of more than 11 (NO) we ask if 11 is an example of more than 11 (NO) we ask if 12 is an example of more than 11 (YES) we ask if 13 is an example of more than 11 (YES) we ask if 11.0001 is an example of more than 11 (YES) It emerges that MORE THAN 11 is equivalant to AT LEAST 11 |
| ||
In this section we present the 8 slide types. Each slide type corresponds to a distinct slide FUNCTION Each slide is preceded by a slide describing - the URL for the reproduced slide - the FUNCTION of the slide - Key points & CONTENT of the slide The 3rd slide type is the LIST-CONTRAST SLIDE | ||
ITEM | DETAILS | |
url | http://www.towson.edu/~rhendel/math231-f02/slide63.htm | |
FUNCTION | LIST all techniques of a domain & hilight CONTRASTS | |
CONTENT | We list:a)4 Boolean connectives b)notation c)Probability formulae | |
|
||
*1 This slide uses HAT data from class. The data was as follows - There were 14 students in class(4 wore hats,10 did not) - There were 7 males and 7 females - 3 students were MALE and had HATS |
(C) Dr Hendel, Sep-02 | |||||
We summarize 4 ways of COMBINING EVENTS And how this affects probability Again we use the class hat data | |||||
METHOD OF CONNECTION | SYMBOL | Arithmetic symbol | RULE | COMPUTATION | |
Complement NOT | H-bar | minus | P(H-bar)=1-P(H) | P(H-bar)=1-10/14 | |
Conjunction AND | Juxtaposition | * | P(HM) = #(H and M)/#S | P(HM)=3/14 | |
Disjunction OR | u | + | P(H u M)=P(H)+P(M)-P(HM) | P(H u M)=4/14+7/14-3/14=8/14 | |
Conditioning*1 IF | / | P(M|H) =P(MH)/P(H)=3/4 | P(M | H)=P(MH)/P(H)=3/4 | ||
|
|||||
*1 We will discuss thoroughly CONDITIONING in the next slide |
| ||
In this section we present the 8 slide types. Each slide type corresponds to a distinct slide FUNCTION Each slide is preceded by a slide describing - the URL for the reproduced slide - the FUNCTION of the slide - Key points & CONTENT of the slide The 4th slide type is the NEW CONCEPT SLIDE | ||
ITEM | DETAILS | |
url | http://www.towson.edu/~rhendel/math231-f02/slide59.htm | |
FUNCTION | Expose students to the issues in a new course concept | |
CONTENT | We introduce the concept of probability by a simple example | |
|
||
*1 This simple example exposes students to 4 concepts - The EXPERIMENT - The POSSIBLE OUTCOMES - The SPACE (of all possible outcomes) - The EVENT The probability measure can then be illustrated using these 4 basic introductory concepts |
(C) Dr Hendel, Sep-02 | ||
4 basic items related to the definition of PROBABILITY | ||
ITEM | VALUE OR APPLICATION | |
EXPERIMENT | Tossing a die one time | |
POSSIBLE OUTCOMES | 1,2,3... | |
SPACE(all possible outcomes) | {1,2,3,4,5,6} | |
The EVENT | EVEN #<----->{2,4,6}*1 | |
The PROBABILITY MEASURE | Counting | |
The PROBABILITY | P(Even)=#Even/#S=3/6*2 | |
|
||
*1 There is alot of confusion here Math textbooks tend to identify the above two descriptions - EVEN - {2,4,6} Actually they are distinct. - EVEN is the UNDERLYING ATTRIBUTE of the outcomes - {2,4,6} is the set of events in the space ASSOCIATED with this attribute To form this set simply go thru all points in the space and see which ones are even. *2 The probability is usually based on COUNTING |
| ||
In this section we present the 8 slide types. Each slide type corresponds to a distinct slide FUNCTION Each slide is preceded by a slide describing - the URL for the reproduced slide - the FUNCTION of the slide - Key points & CONTENT of the slide The 5th slide type is the PROCEDURE SLIDE | ||
ITEM | DETAILS | |
url | http://www.towson.edu/~rhendel/math231-f02/slide56.htm | |
FUNCTION | List the several steps in a procedure | |
CONTENT | We present a 4-step procedure to compute percentiles |
(C) Dr Hendel, Sep-02 | ||||
How do you compute the pth percentile We will illustrate with the 75th Percentile, Q3*1 | ||||
STEP | WHAT TO DO | THE RESULT | 75th percentile | |
0 | Data set | 80,70,90,85,80 | ||
1 | Sort it | 70,80,80,85,90 | ||
2 | n=# Items | n=5 | ||
3 | Lp=(n+1)p/100 | Lp=(5+1)p/100= | L75=3/4*6=4.5 | |
4 | Q3 at Lp-th place | Look up value*2 | 4.5th item=85*3 | |
|
||||
*1 The following notation is used Q1=25th percentile Q2=50th percentile Q3=75th percentile *2 So L_p is the LOCATION of the p-th percentile But the p-th percentile is the VALUE in the L_pth row *3 Either of these answers is correct - the 4.5 th item on the list 70,80,80,85,90 is the 4th item:85 - the 4.5 th item on the list 70,80,80,85,90 is the 5th item:90 - the 4.5 th item on the list 70,80,80,85,90 is the average of the 4th and 5th item: (85+90)/2=87.5 This last method is call LINEAR INTERPOLATION(You are NOT responsible for it) Excel uses a totally different formulae (and gets different answers) to compute the pth percentile. Since there is so much disagreement any of the above answers is ok |
| ||
In this section we present the 8 slide types. Each slide type corresponds to a distinct slide FUNCTION Each slide is preceded by a slide describing - the URL for the reproduced slide - the FUNCTION of the slide - Key points & CONTENT of the slide The 6th slide type is the SPREADSHEET SLIDE | ||
ITEM | DETAILS | |
url | http://www.towson.edu/~rhendel/math231-f02/slide47.htm | |
FUNCTION | Present a spreadsheet method for solving a problem*1 | |
CONTENT | We present a spreadsheet for computing Population SD | |
|
||
*1 It is debatable whether the FORMULA or SPREADSHEET approach is superior. One can hide the SPREADSHEET by simply presenting the formula and then going over the sub-computations in the formula. |
(C) Dr Hendel, Sep-02 | ||||||
We use the same Data as in the Mean Deviation slides We use the same columns with occasional modifications We derive two useful measures: -The Population Variance indicated by the Greek SIGMA-2 -The population Standard Deviation indicated by Greek Sigma | ||||||
C1-Data | c2-Average | c3=C1-c2=Distance from avg | c4=c3^2 | c5=Avg(c4)*4 | c6=Sqrt(c5) | |
38 | 28*1 | 10*2 | 100*3 | 534/5=106.8 | 10.33*5 | |
26 | 28 | -2*2 | 4 | |||
13 | -15 | 225 | ||||
41 | 13 | 169 | ||||
22 | -6 | 36 | ||||
|
||||||
*1 Average = Sum of C1 over # Items in C1 = 140/5=28 *2 c3=c1-c2. So 38-28=10. 26-28=-2. *3 c4=c3^2. eg 10^2=100. Note how the definition of c4 is different for the SD vs the MD *4 c5 = Average (C4) = Sum(C4)/# Items= 534/5=106.8 c5 is called the POPULATION VARIANCE It is denoted by the Greek letter sigma^2 *5 c6 = Sqrt(c5). Sqrt(106.8)=10.33 c6 is called the POPULATION SD (Standard deviation) It is denoted by the Greek sigma |
| ||
In this section we present the 8 slide types. Each slide type corresponds to a distinct slide FUNCTION Each slide is preceded by a slide describing - the URL for the reproduced slide - the FUNCTION of the slide - Key points & CONTENT of the slide The 7th slide type is the OVERVIEW SLIDE | ||
ITEM | DETAILS | |
url | http://www.towson.edu/~rhendel/math231-f02/slide49.htm | |
FUNCTION | Compare several similar course problems--hilight differences | |
CONTENT | We compare the POPULATION SD,SAMPLE SD and MEAN DEVIATION | |
|
||
*1 The emphasis here is on comparing several similar COMPLEX problems. Thus in this example we compare the POPULATION SD, the SAMPLE SD etc Each of these concepts are COURSE CONCEPTS IN THEIR OWN RIGHT. Hence the purpose of the OVERVIEW slide is to compare course items that have a great deal of similarlity |
(C) Dr Hendel, Sep-02 | ||||
We compare the column definitions for MD, Population SD & Sample SD | ||||
Column | Mean Deviation | Population SD | Sample SD | |
c1 | data | data | data | |
c2 | average c1 | average c1 | average c1 | |
c3 | c3=c1-c2 | c3=c1-c2 | c3=c1-c2 | |
c4 | c3 with + sign | c4=c3^2 | c4=c3^2 | |
c5 | Sum(C4)/n*1 | Sum(c4)/n | Sum(c4)/(n-1) | |
c6 | ---------------- | c6=Sqrt(c5) | c6=Sqrt(c5) | |
|
||||
*1 n=# Of data items (Thoughout the course) |
| ||
In this section we present the 8 slide types. Each slide type corresponds to a distinct slide FUNCTION Each slide is preceded by a slide describing - the URL for the reproduced slide - the FUNCTION of the slide - Key points & CONTENT of the slide The 8th slide type is the HOMEWORK SLIDE | ||
ITEM | DETAILS | |
url | http://www.towson.edu/~rhendel/math231-f02/slide101.htm | |
FUNCTION | Examine HomeWork Problems--emphasize subtle distinctions | |
CONTENT | Review sample mean problems: Two issues are studied*1 | |
ISSUE 1 | What justifies using the NORMAL distribution for sample means? | |
ISSUE 2 | How does a student RECOGNIZE that this is a SAMPLE MEAN problem? | |
|
||
*1 This slide summarizes 8 problems on sample means done in class. The slide is a bit terse for someone not in class and needs further clarification for full understanding. These further details are provided in footnotes 2,3. *2 The 6th column entitled NORMAL? presents 3 possible justifications for using the Normal distribution(vs the t distribution) on the sample means - #1: The problem explicitly states that the POPULATION is NORMAL and the POPULATION SD is known - #2: The sample size n >=30 (The point being that a t distribution with n>=30 can be approximated by the normal distribution) - #3: The population standard deviation is given AND It is reasonable to ASSUME that the population is normally distributed *3 The 3rd column entitled WHY SAMPLE MEAN-WHAT KEYWORDS?, presents the phrase in the problem question that would enable the student to recognize that the problem is dealing with SAMPLE MEANS. This column was included in response to student inquiries: (How does a student know that the problem is a Sample mean problem vs a population mean problem). Such phrases as - WHAT PERCENT OF THE SAMPLE MEANS ARE... - FOR A RANDOM SAMPLE...WHAT IS THE PROBABILITY OF THE MEAN.... indicate that the problem is a SAMPLE MEAN (vs a POPULATION MEAN) problem. Note how several of these phrases more clearly indicate that it is a SAMPLE MEAN problem. |
(C) Dr Hendel, Sep-02 | |||||||
From page 293 in the book Notice the emphasis and contrast in the WHY SAMPLE MEAN-WHAT KEYWORDS column. | |||||||
# | Dist type | Why sample mean--what keywords | u | sig | Normal? | SD Sample means | |
29 | Sample mean | What fraction of the samples | 35 | 5.5 | Known | 5.5/sqrt(25) | |
30 | Sample mean | What Percent of sample means | 135 | 8 | Known | 8/sqrt(16) | |
-- | -------- | -------------------------- | ---- | -- | ---- | ---------- | |
31 | Sample mean | likelihood of finding a sample mean | 350 | >=30 | 45/sqrt(40) | ||
32 | Sample mean | likelihood of selecting sample mean | 110000 | >=30 | 40000/sqrt(50) | ||
-- | -------- | ----------------------------- | --- | -- | ---- | ------------ | |
34 | Sample mean | likelihood that sample mean is.. | 18 | 3.5 | Assume | 3.5/Sqrt(15) | |
36 | Sample mean | Likelihood that the sample mean.. | 23.5 | >=30 | 5/Sqrt(50) | ||
-- | ------- | ---------------------------- | ---- | -- | ---- | ----------- | |
37 | sample mean | random sample...prob..mean is.. | 947 | 205 | >=30 | 205/Sqrt(60) | |
33 | Sample mean | For a random sample ..prob of mean | 24.8 | >=30 | 2.5/Sqrt(60) |
| ||
Let us use the theoretical slide types of section IX to show how to construct slides for the topic of COUNTING FUNCTIONS - combinations, permutations and powers. The table below compactly presents the items that are necessary to be presented. | ||
ITEM NEEDED | EXAMPLES | |
name of function | Combination, Permutation | |
notation | n_C_r | |
simple numerical example | 2_C_4=6 | |
rule for function | n!= n x (n-1) x (n-2)... | |
special (initial) values | 0!=1!=1 | |
non-simple numerical examples | 4! = 4 x 3 x 2 x 1 = 24 | |
Function-word problem map | SETS-combinations;SEQUENCES-permutations | |
Sets vs sequences | Does ORDER count? Are items REPEATED? | |
|
||
*1 http://www.Towson.Edu/math231-f02/slide66.htm http://www.Towson.Edu/math231-f02/slide67.htm http://www.Towson.Edu/math231-f02/slide68.htm http://www.Towson.Edu/math231-f02/slide69.htm |
| ||
The above analysis naturally gives rise to 4 slides The 4 slide titles are presented below along with the slide field names. Footnotes indicate how each of these 4 slides are classified in the 8 slide types The actual 4 slides are presented immediately below. | ||
This slide does the following | Fields in the slide | |
LIST 4 counting functions*1 | English Name, Math Notation,simple examples | |
LIST functions-Rules*2 | Function, Rule, special values, examples | |
List word problems-functions*3 | Function,Typical word problem, solution | |
SEQUENCES vs SETS vs CODES*4 | Does ORDER matter? Are items REPEATED? | |
|
||
*1 This is a LIST CONTRAST slide (It lists all 4 counting functions relevant to COUNTING problems and contrasts their notations and names) *2 This is a LIST-CONTRAST SLIDE (It lists the 4 counting functions and contrasts their algorithmic rules) *3 This is a DICTIONARY SLIDE (It shows the CORRESPONDENCE between WORD PROBLEMS (eg # sets, # sequences) and COUNTING FUNCTIONS *4 This is a DISTINCTION SLIDE (It distinguishes between SETS, SEQUENCES and CODES) |
(C) Dr Hendel, Sep-02 | |||
In this slide we introduce the NAMES & NOTATIONS for the 4 functions Future slides will indicate how to compute & what word problems they solve | |||
NAME OF FUNCTION | NOTATION | NUMERICAL EXAMPLES | |
Factorial | n! | 3! 4! | |
Permutation | n_P_r | 5_P_3 *1 | |
Combination | n_C_r | 5_C_3 *1 | |
Power | n^r | 5^3 | |
|
|||
*1 Answer to student question: The BIGGER number is always on the left (5_P_3 is correct; 3_P_5 will not be used in this course) |
(C) Dr Hendel, Sep-02 | ||||
How to compute with them | ||||
FUNCTION | SPECIAL VALUES | RULE | EXAMPLE | |
n! | 0!=1 1!=1 | n!=n*(n-1)*(n-2)...*1 | 4!=4*3*2*1=24 | |
n_P_r | n_P_0=1 | n_P_r =n*(n-1)...(n-r+1) *1 | 7_P_3=7*6*5=210 *1 | |
n_C_r | n_C_0=1 | n_C_r=n/1*(n-1)/2*...*(n-r+1)/r *2 | 7_C_3=7/1*6/2*5/3=35 *2 | |
n^r | n^0=1 | n^r =n*n*n...n (r times) | 4^3=4*4*4=64 | |
|
||||
*1 The book uses the rule n_P_r= n!/r!. However the rule I give is simpler computationally ------------------------------------------------------- -- Multiply downward starting at n(left side number) -- have r items in produce (r is right side number) ------------------------------------------------------- See *10 for an extended example SEE PROBLEMS-DONE page for a list of book examples done *2 The book uses the rule n_C_r = n! / (r! (n-r)!) However the rule I give is simpler computationally ------------------------------------------------------ -- multiply downward starting at n(Left side number) -- let the denominators go upward starting at 1 -- stop when the denominator = r (Right side number) ------------------------------------------------------ | ||||
|
||||
*10 So 7_P_3 is computed as follows - Start at 7 the left hand # in 7_P_3 - Use 3 multiplicands (3 is the right hand #) EXAMPLE: 7_P_3 7 x 6 x 5 = 210 1st # 2nd # 3rd # In answer to student questions: -------------------------------------------- If you understand the above description then forget the abstract notation and simply learn the rule...To show work you can suffice with showing numerical work -------------------------------------------- *11 EXAMPLE: 7_C_3 - Start numerator at 7 (Left hand #) on top - Start denominator at 1 - Go upwards to 3 (Right hand #) 7 6 5 -- x -- x -- = 35 1 2 3 1st # 2nd # 3rd # |
(C) Dr Hendel, Sep-02 | |||
What word problems can be done with them | |||
FUNCTION | TYPICAL WORD PROBLEM | SOLUTION | |
n! | NA | NA | |
n_P_r | How many SEQUENCES of 3 items from 7 | ANSWER: 7_P_3=210 | |
n_C_r | How many SETS of 3 items from 7 | ANSWER: 7_C_3=35 | |
n^r | How many CODES of 3 items from 7 | ANSWER:7^3=343 |
(C) Dr Hendel, Sep-02 | ||||
Differences between SEQUENCES, SETS, CODES (NOT IN BOOK but very helpful) | ||||
ITEM | DO YOU CARE ABOUT ORDER? | DO YOU ALLOW REPETITION | EXAMPLE*1 | |
SEQUENCES | Yes | No | route 3 cities | |
SETS | No | No | 3 stat Profs | |
CODES | Yes | Yes | Phone# | |
|
||||
*1 Many examples were done in class. Please see the PROBLEMS-DONE page |
| |||
As indicated in the introduction the above methods have been particularly helpful in calculus and stat courses. I however have encountered resistance in upper level courses due to notational problems. For example, Students simply do not relate well to text substitutes for integral signs. Here is a brief description of courses where these methods worked. Footnotes indicate attempts to improve other courses. | |||
COURSE | DO SLIDES WORK? | WHY | |
Calculus | Yes | Notepad=blackboard | |
Statistics | Yes | Notepad=blackboard | |
Upper level | No*1 | Notation(Integral,quotients) | |
|
|||
*1 One student suggested that if problems are worked out in say mathematica and the appropriate exe files are on the system then a hyperlink to a worked out problem in mathematica would automatically open. This would solve the problem of presenting worked out problems. The description of theory and contrasts could probably still be accomplished in English. Hence future versions of this approach will focus on techniques relevant to upper level courses. |