Question

Assume that the sample is a simple random sample obtained from a normally distributed population of flight delays at an airport. Use the table below to find the minimum sample size needed to be 95​% confident that the sample standard deviation is within 1 % of the population standard deviation. A histogram of a sample of those arrival delays suggests that the distribution is​ skewed, not normal. How does the distribution affect the sample​ size? sigma To be​ 95% confident that s is within ​1% ​5% ​10% ​20% ​30% ​40% ​50% of the value of sigma​, the sample size n should be at least ​19,205 768 192 48 21 12 8 To be​ 99% confident that s is within ​1% ​5% ​10% ​20% ​30% ​40% ​50% of the value of sigma​, the sample size n should be at least ​33,218 ​1,336 336 85 38 22 14

Answer 1

A histogram of a sample of those arrival delays suggests that the distribution is? skewed, not normal. How does the distribution affect the sample? size?

option c is correct i.e;

The computed minimum sample size is not likely correct.
Because sample size is calculated basis normality assumption whereas in this scenario the normality assumption is violated since the distribution is skewed.

from the given information

the minimum sample size needed to be 95% confident interval that the sample standard deviation is within 1% at the population standard deviation

therefore the minimum sample size needed is 19205