A national restaurant chain claims that their servers make an average of $12.85 in tips per hour, with a standard deviation of $2.15. The servers at the restaurant chain's location in Dallas make an average of $8.65 in tips per hour. Given that the data is approximately normal, find the probability that a server, chosen at random, will make more than $8.65 in tips per hour.

Question

Vocaloid · Answer

Calculate the z score

(Dallas tips - national average)/standard dev

Then use a z table to find the associated probability. This will give you the probability of making less than 8.65 so just take 1 - the result to get the probability of getting greater than 8.65