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.

Respuesta :

Answer:

[tex]19.55\pm2.145[/tex]

Step-by-step explanation:

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