Question

If the sample standard deviation had turned out to be 9 centimeters (and all else had turned out the same), how would the confidence interval have been affected?

Answer 1

Determine how would the the confidence interval have been affected by changing the standard deviation

From the infromation, given that the value of the sample standard deviation had turned out to be 9 centimeters and given that rest of the values remains same.

That is, given that standard deviation is changed to 9 which may be the higher or lower than the previous number of the standard deviation that has been used.

If the SD increases to 9, the Margin of increases, as result the confidence interval gets wider.

If the SD decreases to 9, the margin of error gets decreased as result the confidence interval gets narrower.