Question

In a situation where the sample size was 28 while the population standard deviation was increased, what would be the impact on the confidence interval?

A) It would become narrower due to using the t distribution
B) It would widen with more values
C) It would become wider due to using the z distribution
D) It would become wider with more dispersion in values

Answer 1

C; It would become wider due to using the z-distribution

Explanation:

Mathematically, we go on to look at the formula for confidence interval calculations here

The formula involves multiplying z by the s

which is the z-value and the standard deviation

Increasing the standard deviation value means we are increasing the product of multiplying z and s

This means that we are getting a larger value for the multiplication

Thus, we now have a wider confidence interval value as a result of a larger product

So this means that the CI would become wider due to the usage of the z-distribution