Answer:
Step-by-step explanation:
Part A :
The requirements (assumption) for testing population mean
1) The Sample are autonomous (not dependent) and normally distributed
2) If the sample size is large ( n >30) then the sampling distribution approaches to normal distribution.
therefore the necessities that are required for testing the claim that the sample is from population with a mean bigger than 80 sec is
D : Either the population is normally distributed or n > 30 or both.
Part B :
To draw normal quantile plot by using R
v <-c(83,13,572,49,0,58,195,41,165,0,2,59)
qqnorm(v)
qqline(v)
From normal qq plot which can be seen from the below attached image, we can see that almost all point on or near the straight line (except one outlier 572).
hence correct answer is
Yes . A normal quantile plot suggests that the sample is from a normally distributed population and there are observation below and above 80.
