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QSCI 381
LAB 9 Exercise
November 26, 2014
1.
An organization believes that the number of prospective home buyers who want their next
house to be larger, smaller, or the same size as their current house is uniformly distributed. To
test this claim, you randomly select 800 prospective home buyers and ask them what size they
want their next house to be. The results are shown in the table below. At α = .05, can you
reject the claim that the distribution is uniform?
Response Frequency
Larger
285
Same size
224
Smaller
291
a) Identify the claimed distribution and stat the null and alternative hypothesis.
b) Find the critical value and identify the rejection region
c) find the chi square test statistic
d) Decide whether to reject or fail to reject the null hypothesis
e) Interpret the decision in the context of the original claim
2.
The results of a random sample of patients with obsessive compulsive disorder treated with a
drug or with a placebo are shown in a contingency table. At α = .1, can you decide that the
treatment is related to the result? On the basis of these results, would you recommend using
the drug as a part of a treatment for obsessive-compulsive disorder?
Result
Improvement
No Change
a)
Drug
Treatment
Placebo
39
54
25
70
Identify the claim and state the null and alternative hypothesis
b) Determine the degrees of freedom, find the critical value, and identify the rejection region
c) Calculate the test statistic.
d) Decide to reject or fail to reject the null hypothesis. Then interpret the decision in the
context of the original claim.