# A random sample of families was taken in order to estimate the relation between fertility and...

## Question:

A random sample of families was taken in order to estimate the relation between fertility and level of education (measured in number of years). A confidence interval needs to be constructed for the slope of the regression line. The social worker in charge of the project is debating whether to use a 90% or a 95% confidence interval.

Which of the following statements about the length of these intervals is true?

A. The 95% confidence interval will be wider than the 90% confidence interval.

B. The 95% confidence interval will be narrower than the 90% confidence interval.

C. Both intervals will be of the same length, because they are computed from the same sample.

D. The length of the confidence interval will depend on the sample size, not on the confidence level.

E. The length of the confidence interval will depend on the sample standard deviation, not on the confidence level.

## Confidence Interval

The confidence interval is the interval estimation which provides the lower limit and upper limit. The confidence level is the level of possibility at which the value of population parameters lies between the bound of the confidence interval.

Given Information

Confidence level: 90% or 95%

The correct option is option(A), since the higher confidence level 95% leads to higher critical value and margin of error which increases the width of the confidence interval.

Therefore, the correct option is an option(A). 