The awnser is c give me brainliest
Answer:



Step-by-step explanation:
Given

Solving (a): Point estimate of difference of mean
This is calculated as: 


Solving (b): 90% confidence interval
We have:


Confidence level is: 



Calculate 


The z score is:

The endpoints of the confidence level is:






Split


Hence, the 90% confidence interval is:

Solving (c): 95% confidence interval
We have:


Confidence level is: 



Calculate 


The z score is:

The endpoints of the confidence level is:






Split


Hence, the 95% confidence interval is:

The answer is 70/100ths i am pretty sure
You must calculate how many ways can 2 people be selected from 65.
The formula is:
n! / r! * (n-r)! =
65! / 2! * 63! =
65*64*63! / 2 * 63! =
65*64 / 2 =
2,080 handshakes
Source:
http://www.1728.org/combinat.htm