Question

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

Short answer

Confidence Level of$99\%$is used.

Step-by-step solution

Given Information

We are given that

Determining Confidence Level Used

Confidence Level is calculated as $\frac{25}{25}=1$

$100\%$

• Red line implies those sample means which have no true population mean.
• There are zero samples among given $25$samples not containing true proportion.
• Hence, $25$samples from $25$samples has true population.
• The confidence level which is closest is$99\%$