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What is the reference value? Does it come from the sample data? Is it known or unknown?
How is a paired t-test similar to and different from an ordinary t-test for just one sample?
What can you say about your lifetime track record in terms of correct decisions to accept true null hypotheses?
What new assumption is needed for the unpaired t-test to be valid for small samples? What can you do if this assumption is grossly violated?
Compute your own two-sided 95% confidence interval. Compare your results to the margin of error, if this is reported in your source.
The preliminary survey results just came back on the specialty catalog project, and they look great! The average planned order size was $42.33
Which one usually includes the case of pure randomness? Which one has the burden of proof? Which one has the benefit of the doubt?
Briefly describe the steps involved in performing a two-sided test concerning a population mean based on a confidence interval.
Consider each assumption in turn. What happens if the assumption is not satisfied? What, if anything, can be done to fix the problem?
When are you allowed to perform a one-sided test? What should you do if you are not sure if it is allowed?
Suppose you have an estimator and would like to test whether or not the population mean value equals 0. What do you need in addition to the estimated value?
Describe the general process of constructing confidence intervals and performing hypothesis tests using the rule of thumb.
Obtain an estimated value and its standard error (either from data or by educated guess) for each of two situations important to your business interests.
Why should you be hesitant to use this sample and the methods of this chapter to compute a confidence interval for the percentage of women?
Find the 95% confidence interval for the population mean quality. Find the 95% prediction interval for the quality of the next measurement.
Find the one-sided 99% confidence interval for the population mean caffeine content of a cup of coffee that claims “at least….”
From a list of the 729 people who went on a cruise, 130 were randomly selected for interview.
Draw a histogram indicating the average and median values, and briefly comment on their relationship. Are they the same? Why or why not?
Find the 95% confidence interval for the amounts that your regular customers spent on your products last month.
Find the one-sided 99% confidence interval that claims that the population percent is no more than some amount.
A nationwide poll claims that the margin of error is no more than 4.3 percentage points for questions asked of half the sample (at the 95% confidence level).
A survey of 21 business intelligence analysts, who had been in their current positions from 10 to 20 years, revealed $90,734 as the average salary.
A survey of eight vice presidents of information technology and information systems, who had been in their current positions for 10 years or less.
During a 1-week experiment, motion was added to in store sales displays at a random sample of your firm’s stores nationwide.
Write a brief paragraph describing how these confidence intervals shed important light on your candidate’s chances.