Question

A random sample of 41 cars in the drive-thru of a popular fast food restaurant revealed an average bill of $19.55 per car. The population standard deviation is $6.33. Estimate the mean bill for all cars from the drive-thru with 97% confidence.

Answer 1

Answer:

$19.55\pm2.145$

Step-by-step explanation:

We use the equation $\bar x\pm z^*\sigma/\sqrt n$, where $\bar x=19.55$, $\sigma=6.33$, $n=41$, and $z^*=2.17$. We obtain $z^*$ from the z-score of a 0.97 confidence level.