Question

"Refer to the accompanying data display that results from a sample of airport data speeds in Mbps. Complete parts​ (a) through​ (c) below. TInterval ​(13.046,22.15) x= 17.598 Sx = 16.01712719 n= 50 a. Express the confidence interval in the format that uses the​ ""less than"" symbol. Given that the original listed data use one decimal​ place, round the confidence interval limits accordingly."b. Identify the best point estimate of μ and the margin of error.

c. In constructing the confidence interval estimate of μ​, why is it not necessary to confirm that the sample data appear to be from a population with a normal​distribution?
A. Because the sample standard deviation is​ known, the normal distribution can be used to construct the confidence interval.
B. Because the sample is a random​ sample, it can be assumed that the sample mean is from a population with a normal distribution.
C.Because the population standard deviation is​ known, the normal distribution can be used to construct the confidence interval.
D. Because the sample size of 50 is greater than​ 30, it can be assumed that the sample mean is from a population with a normal distribution.

Answer 1

it is not necessary to confirm that the sample data appear to be from a population with a normal ​distribution;

D. Because the sample size of 50 is greater than​ 30, it can be assumed that the sample mean is from a population with a normal distribution

Explanation:

Normal distribution which is otherwise known as the Gaussian distribution, it is a probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean.

The arithmetic mean or average; is the sum of a collection of numbers divided by the total numbers in the collection.