Math 156 Sample Exam 3 Formulas Binomial mean np standard ...

6. a) Consider two confidence intervals for the mean of a population:
413.1 ± 3.12 and 413.1 ± 2.62 . One is a 95% confidence interval and one is a 99% confidence
interval. Which is which Defend your answer.
b) Consider two confidence intervals for the mean of a population:
217.2 ± 4.12 and 217.2 ± 3.43 . One is from a sample of size 25 and one is from a sample of size
36. Which is which Defend your answer.
7. a) Suppose we wish a 99% confidence interval to have a margin of error of .25, and the
population standard deviation is assumed to be 1.5. Determine what sample size is required.
b) Suppose the standard error of the mean is .05 and the sample size is 900. About how big is the
standard deviation
c) In a recent study it was claimed that lengths of trout in Lake Pueblo have a mean different than
those upstream, which average 14 inches. State the null and alternative hypothesis in this setting.
d) Suppose a test results in a p-value of .16. What can you say about the null hypothesis and
alternative hypothesis