CREATING WEB BASED COURSES

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

SECTION I: GOALS

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

SECTION II: AUDIENCE

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
COMMENTS
*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.

SECTION III: THE KEY IDEAS

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
COMMENTS
*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

LONGER FOOTNOTES
*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.

SECTION IV: HISTORICAL DEVELOPMENT #1


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

SECTION IV: HISTORICAL DEVELOPMENT #2


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

SECTION V: OVERVIEW & REFERENCES


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
COMMENTS
*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.


SECTION VI: BACKGROUND INFO ON COURSE/SYLLABUS #1


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
COMMENTS
*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

SECTION VI: BACKGROUND INFO ON COURSE/SYLLABUS #2


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
COMMENTS
*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

SECTION VII: THE REST OF THIS PAPER

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

SECTION VIII: THE ANATOMY OF A SLIDE #1


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)
COMMENTS
*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

LONGER FOOTNOTES
*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.

AVG vs DISPERSION


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

SECTION IX: THE 8 SLIDE TYPES #1


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

AVG vs DISPERSION
(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

SECTION IX: THE 8 SLIDE TYPES #2


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...

NEW DISTRIBUTION APPROACH # 2
(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
COMMENTS
*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

LONGER FOOTNOTES

*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

SECTION IX: THE 8 SLIDE TYPES #3


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
COMMENTS
*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

BOOLEAN CONNECTIVES
(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
COMMENTS
*1 We will discuss thoroughly CONDITIONING in the next slide

SECTION IX: THE 8 SLIDE TYPES #4


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
COMMENTS
*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

PROBABILITY
(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
COMMENTS
*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

SECTION IX: THE 8 SLIDE TYPES #5


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

PERCENTILES #2
(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
COMMENTS
*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

SECTION IX: THE 8 SLIDE TYPES #6


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
COMMENTS
*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.

POPULATION VARIANCE & SD
(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
COMMENTS
*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

SECTION IX: THE 8 SLIDE TYPES #7


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
COMMENTS
*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

COMPARISON OF MD vs SD
(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)
COMMENTS
*1 n=# Of data items (Thoughout the course)

SECTION IX: THE 8 SLIDE TYPES #8


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?
COMMENTS
*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.

SAMPLE MEAN PROBLEMS #1
(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)

SECTION X: AN EXTENDED EXAMPLE #1 *1


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?
COMMENTS
*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

SECTION X: AN EXTENDED EXAMPLE #2

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?
COMMENTS
*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)

4 COUNTING FUNCTIONS #1
(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
COMMENTS
*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)

4 COUNTING FUNCTIONS #2
(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
COMMENTS
*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)
------------------------------------------------------

LONGER FOOTNOTES
*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 #

4 COUNTING FUNCTIONS #3
(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

4 COUNTING FUNCTIONS #4
(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#
COMMENTS
*1 Many examples were done in class. Please see the PROBLEMS-DONE
page

SECTION XI: FUTURE DEVELOPMENTS


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)
COMMENTS
*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.