The following mesaurements were recorded for the drying time, in hours of a certain brand of latex paint.

3.4, 2.5, 4.8, 2.9, 3.6, 2.8, 3.3, 5.6, 3.7, 2.8, 4.4, 4.0, 5.2, 3.0, 4.8

Assuming that the measurements represent a random sample from a normal population,

a) find the 95% confidence interval for the means

b) find the 95% confidence interval for the variances

c) with 0.01 level of significance is it justifiable to claim that there the mean is less than 3.75 hours?

d) is there a reason to believe that the variance is equal to 1?

I tried solving this a little while ago but I just can't understand it. My professor teaches us just too fast and gives us tons of notes to copy that's why I can't keep up with what he is teaching. I based my computations on my notes but still I could not do it. I can't think of the correct null hypothesis and alternative hypothesis for this. Any help will be appreciated, thank you very much.