Here's an opportunity for a couple extra stamps: the answer key I gave you today has an error (in the handwritten question part)...can you find it? If so, fix it and tell me my error before or after class for a few stamps!
Here's an outline of the next 2 weeks, in case you're curious:
Thursday/Friday: "New stuff." (Paired t-tests and intervals)
Monday: Practice (all t-tests/intervals)
Tuesday: TEST on t-tests and intervals (all of them)
Weds-Friday: "New stuff." (Chi-square tests)
And lastly, here's tonight's homework questions (if you can't find yours):
The paper “Ladies First?” A Field Study of
Discrimination in Coffee Shops (Applied
Economics [2008]) describes a study in which researchers observed wait
times in coffee shops in Boston. Both wait time and gender of the customer were
observed. The mean wait time for a sample of 145 male customers was 85.2
seconds; the mean wait time for a sample of 141 female customers was 113.7
seconds. The sample standard deviations (estimated from graphs in the paper)
were 50 seconds (for males) and 75 seconds (for females). Suppose that these
two samples are representative of the populations of both female and male
coffee shop customers.
1. Verify that the conditions for a 2-sample t-test/interval
are satisfied.
2. Estimate the difference in mean wait times for males and
females using 98% confidence.
3. Interpret this interval.
4. Is there convincing evidence that the mean wait time
differs for males and females? Test the
relevant hypotheses using a significance level of 0.05.
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