write out and show all work clearly, thanks!

8. Data was collected from a random sample of 20 customers at both US Bank and TCF Bank. The mean wait time at both banks was 5 minutes. The Standard Deviation for the TCF Bank wait time is s = .476 minutes. The Standard Deviation for the US Bank wait times is s = 1.82 minutes Compare the two standard deviations and write a sentence explaining what the difference in standard deviations means if you are a customer waiting in line at either bank. (Note: I can see that the standard deviation for TCF is lower than that of US Bank...tell me more than that). (3 pts) I 9. A study on the enhancing the effect of coffee on long-term memory found that 35 participants given 200 mg of caffeine performed better on a memory test 24 hours later compared to the placebo group that received no caffeine. (4 pts) a) There was a probability of 0.02 that the difference between the coffee group and the placebo group was due to chance. Are the results of this study statistically significant? Explain. b) Another group was given a dose of 300 mg and performed better than the 200 mg group. There was a 0.75 probability that this difference was due to chance. Are the results of this study statistically significant? Explain