Question

Describe the relationship you find between the confidence level C and the span of the confidence interval. When you move C to 99% to 90%.

Answer 1

The confidence interval is directly proportional to the confidence level , because the margin of error which is also directly proportional to the Zc that is calculated using the confidence level as ME= Zc*SE where SE is the standard error.

TheZc value increases as the confidence level increases hence makes a increase in margin of error which makes the interval wider.

Thus the conclusion that can be made is that the interval width increases as the confidence level increases and vice versa.