Confidence Intervals · Medium problem

We are $95\%$ confident that the mean life of all such batteries is between $18.2$ and $21.8$ hours

$95\%$ of batteries last between $18.2$ and $21.8$ hours

There is a $95\%$ chance that the sample mean is between $18.2$ and $21.8$ hours

$95\%$ of future samples of $40$ batteries will have means between $18.2$ and $21.8$ hours