Question

How confident? The figure at top right shows the result of taking $25$SRSs from a Normal population and constructing a confidence interval for each sample. Which confidence level—$80\%,90\%,95\%$, or $99\%$—do you think was used? Explain.

Short answer

The nearest confidence level is $99\%$.

Step-by-step solution

Given Information

The result of taking $25$ SRSs:

Explanation

The red lines under the curve represent the sample means that do not contain the true population proportion.

We note that there are $0$out of the $25$samples that do not contain the true proportion and thus $25$out of the $25$samples contain the true proportion:

$\frac{25}{25}=1=100\%$

The nearest confidence level is $99\%$(although $95\%$could also be a possible used confidence level).