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Inferential Statistics

Objective: Testing for reliable relationships (Wouldn't you like to be able to do this in your personal life?)

Prerequisite: Ch. 19

Assignment due by: Thurs. 6/7, 8 pm

Background: Read through Chapter 19. Don’t try to understand all the calculations. All of them can be done on a computer using statistical software. On the exam in this course, you will not be asked to do a t-test, Chi square, or ANOVA, or to calculate an r. The important things to learn are when to use the tests, what they do, and the meaning of common terms and statistical notations. After reading the chapter, you should be able to answer Sample Problem 1 on P. 286. If you want experience in doing the statistical tests described in the chapter (not required for the PSC41 exam) you can do Sample Problems 2-4, which require only a calculator, and the answers are found on P. 288.

Assignment:

Here are some selected data from the Cat-Dog interview. Look them over and solve the 4 problems. When you are ready, fill out the answer form.

PROBLEM #1
Hypothesis: Males are more likely than females to own dogs.

  1. For the results below, what statistical test would you use to test the hypothesis?
  2. Give the reason for your choice.
PET
GENDER
OF OWNER		 Cat (n=18) Dog (n=26)
Female 43.8% 56.3%
Male 33.3% 66.7%

PROBLEM #2
Question: Is there a difference between cat and dog owners, with respect to whether or not they would replace their current pet with the same species?

  1. For the results below, what statistical test would you use answer the question?
  2. Give the reason for your choice.
CURRENT ANIMAL
REPLACEMENT
CHOICE		 Dog (n=26) Cat (n=18)
Same 50.0% 84.6%
Different 16.7% 0.0%
None 33.3% 15.4%

PROBLEM #3
Hypothesis: Dogs are more sociable than cats.

The table below shows the results for the question "How outgoing and sociable is the animal with visitors?" rated on a scale of 1 to 5 (1 = Not sociable, 2 = Low, 3 = Somewhat, 4 = Moderately, 5 = Very)

  1. What statistical test would you use to test the hypothesis?
  2. Give the reason for your choice.
Animal N Mean SD
Cats 19 3.17 1.26
Dogs 26 4.27 1.06

PROBLEM #4
We also asked the owners to rate themselves on their sociability.

  1. What statistic would we use to find out if there is a relationship between animal sociability and owner sociability?
  2. Give the reason for your choice.

I'm ready -- take me to the answer form.