A hypothetical study concerned with estimating the amount of marijuana use per year

among a teenage population obtained a sample of 110 high (n=110)school students.

With the following sample statistics, construct a 75% confidence interval around the mean number of times this sample used marijuana in a given 1-year period:

Mean = 6.5 times per year

sd= 4.2 times per year

n = 110

4. Using the data in question #3, construct a 90% confidence interval around the mean number of times marijuana was used.