Question

A study was conducted to test whether marijuana use impacts your short-term memory. A simple random sample of college students that do NOT use marijuana was taken, and given a memory test in which they were shown items in a particular order then asked to recreate that ordering. A second simple random sample was taken of college students that use marijuana 4 - 7 days per week, and they were given the same memory test.

A higher score on the memory test indicates better memory recall.

μ1μ1 indicates the population mean memory recall score for non-users.

μ2μ2 indicates the population mean memory recall score for marijuana users.

The 99% confidence interval for the difference of means was found to be:

2.1 < μ1−μ2μ1-μ2 < 15.9

Can we support the claim that marijuana users have less short-term memory than non-users?

• Yes
• No

Why or why not?

Answer 1

a 99% confidence interval for the difference of means = (2.1 , 15.9)

Since the confidence interval does not include 0, so we can say that the population mean memory recall score for non users and marijuana users are significantly different.

Moreover,

lower boundary of the interval > 0, so at 99% level of confidence or at 1% level of significance, we can conclude that marijuana users have less short-term memory than non-users.

ans-> Yes