Adelivery driver has an average daily gasoline expense of $55.00. the standard deviation is $10.00. the owner takes a sample of 54 bills. what is the probability the mean of his sample will be between $45.00 and $65.00?

step 1. calculate the z-score for $45.00.

step 2. give the probability for step 1. %

step 3. calculate the z-score for $65.00.

step 4. give the probability for step 3. %

step 5. add the probabilities from steps 1 & 3.