a. Customer bills
b. Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.
c. 95% = mean ± 1.96 SD
d. Calculate Z score and proportion.
proportion (x) = 12
Solve for x.
The customer bills in a family restaurant are normally distributed. The bills mean is $28 and has a standard deviation of $6.
a. Identify what the random variable you are measuring is in this problem.
b. What is the probability that a randomly selected bill will be at least $39.10?
c. What percentage of the bills will be less than $16.90?
d. What are the minimum and maximum of the middle 95% of the bills?
e. If twelve of one day's bills had a value of at least $43.06, how many bills did the restaurant collect on that day?
1 answer
1 answer