1. Warm-up 4.4 Designing Experiments
In order to assess the effects of exercise on reducing cholesterol, a
researcher sampled 50 people from a local gym who exercise regularly
and 50 people from the surrounding community who do not exercise
regularly. Each subject reported to a clinic to have their cholesterol
measured. The subjects were unaware of the purpose of the study, and
the technician measuring the cholesterol was not aware of whether the
subject exercises regularly or not.
What type of study is this?
What are the units?
What are the conditions of interest being studied?
4) What are some possible error in the sampling that may affect the results?

2. H.W. Discussion on
1) 4.2 E# 16, 18, and 19
2) 4.3 P#27, E#23 and 24

3. More Examples of Parts of Experiments
A nutritionist wants to study the effect of storage time (6,
12, and 18 months) on the amount of vitamin C present
in freeze dried fruit when stored for these lengths of
time. Vitamin C is a measured in milligrams per 100
milligrams of fruit. Six fruit packs were randomly assigned
to each of the three storage times. The treatment,
experimental unit, and response are respectively:
A. A specific storage time, amount of vitamin C, a fruit pack.
B. A fruit pack, amount of vitamin C, a specific storage time.
C. Random assignment, a fruit pack, amount of vitamin C.
D. A specific storage time, a fruit pack, amount of vitamin C.
E. A specific storage time, the nutritionist, amount of vitamin C.

4. More examples
Some people claim they can get relief from migraine
headache pain by drinking a large glass of ice water.
Researchers enlist people that suffer from migraines. When
a participant gets a migraine, he or she will take a pain
reliever or a placebo. Half will also drink a large glass of ice
water. Participants will then report the level of pain relief
they experience.
Identify which of the following are the factors and levels.
People that experience migraines
Levels of pain relief
Presence of Migraine
Pain reliever or placebo, ice water or no ice water

5. 4.4 Designing Experiments to Reduce Variability

6. Example of Designing an experiment
You have been asked to select 20 participants for a drug trial that
compares two different treatments for migraine headaches. The
researcher have requested a block design (male/female) with control
groups for each block. You have been given a list of people willing to
participate in the trial, numbered 01 to 87. The first 42 people are
female; the rest are male.
Sketch a diagram for the design of this experiment
In paragraph form, clearly explain how you will select the subjects for
each block.   

7. Using a random # Digit Table
Beginning at line 123 of the random digits table (below), select the 10 women. Then begin at line 125 to select 10 men. (1 point)

8. Matched Pair Experimental Design
A matched pairs design is a special case of a randomized block design. It can be used when the experiment has only two treatment conditions; and subjects can be grouped into pairs, based on some blocking variable. Then, within each pair, subjects are randomly assigned to different treatments.
The table to the right shows a matched pairs design for a hypothetical medical experiment, in which 1000 subjects each receive one of two treatments - a placebo or a cold vaccine. The 1000 subjects are grouped into 500 matched pairs. Each pair is matched on gender and age. For example, Pair 1 might be two women, both age 21. Pair 2 might be two men, both age 21. Pair 3 might be two women, both age 22; and so on.

9. Last page 2 warm-ups Next one is for next block
Another sheet for next block
This sheet for Day of Test

10. Start the quiz once you get it.
Quiz Directions
Start the quiz once you get it.
Answer ALL short response in complete sentences
Once you are finished, bring up your quiz.
Start your h.w. 4.3 #26 and 27; 4.4 E#34 and 38.
Notebook Check next block
1) ) 4.2 and 4.3 3) pts each x 3 = 75 pts
15 pts for notes 10 pts for warm-up
25 definitions, 1 pt each for 25 pts
Bring your textbook next time for the chapter review out
of the textbook.

11. H.W. Answers 4.2 E # 16, 18 and 19; 4.3 P#27, E#23 and 24
E16 a. A simple random sample will be difficult because if each cookie is a unit. So some how all cookies should be numbered to be randomly selected. A bag will be opened and wasted to collect data from a randomly selected cookie. b. Cluster sampling would involve randomly selecting an entire bag and collecting the data for all cookies in that bag. c. It all depends on time and money. If you don’t have much money but a lot of time cluster sampling would work. If you have a lot of money but not necessarily time, two-stage cluster sample would be better.

12. 4.2 E 18 and 19
E # /30 means that you could potentially check every 20th page. But systematic sample has a random start, so use a random number generator to select a random page from 1 to 20 to start, and then check every 20th page from there. E#19 Since there are only 5 farms stratified sampling would be best. That way data is collected from all 5 farms and the average can predict the crop yield for all 5. Averages may be found for the random samplings within each strata to show more precise predictions of average crop yields.

13. 4.3 P#27, E#23 and 24
The first factor is the brand of paper towel, with levels brand A and brand B. The second factor is wetness, with levels dry and wet. The response variable is the number of pennies the towel can hold before breaking. b. Randomize the assignment of wet or dry to each set of 20 towels (10 from each brand to each treatment) and the order of testing. There are four treatments: brand A wet, brand A dry, brand B wet, brand B dry. Write each treatment name on five slips of paper, then draw to determine the order. The experimental units are the 20 time towel combinations in which the tests will be performed. c. This is an experiment, although the results may not generalize beyond the towels tested unless it can be established that they are essentially The same as all towels of these brands. E#23 This is an example of an observational study. There is no treatment. You are only observing how long it takes the children to solve the puzzle. Then you are using the data to compare the results for grade levels. E#24 Observational study.