Know how to calculate sample size: A restaurant would like to estimate the average $ amount of a take-out order. The standard deviation is $15. If a 99% confidence level and an interval (error) of $5 is desired, how many customers should be in the sample?
Which of the following examples would use the z-distribution:______.
a. x = 100; µ = 99; s = 5; n = 70
b. x = 50; µ = 53; σ = 7; n = 15
c. x = 7; µ = 4; s = 1; n = 20
d. x = 15; µ = 17; σ = 3; n = 45