Answer: C. 
Step-by-step explanation:
The confidence interval for difference of two population mean is given by :-

Given : Level of significance : 
Then , significance level : 
Critical value : 


Hence, a 99% confidence interval for the difference between the mean wait times of everyone who rode both rides 
Count the votes, counting each sophomore ballot as 1.5 votes and each freshmen ballot as 1 vote.
ur doing this because there is 200 more freshmen then sophomores...and if u count each sophomore vote as 1.5, it would make up for the 200 more freshmen
Try rctanguular prism i think it is that
T=65$+(65$*.06)
T=65$+3.9$
T=68.9$