Retail store daily sales are normally distributed with a mean (MEANP) of 53,000.00 and a standard deviation (STDEV.P) of 500.00. Find the probability that if you randomly select a day, its sales are greater than 53,120 (hint: since this problem uses all population values, this is actually a review of a chapter problem) (check figure: 40.52%).
X - MEANP = 3120
STDEV.P = 500.00
Z = (X - MEANP) / STDEV.P = 120.00 / 500.00 = 0.24
The probability that a randomly selected day's sales are greater than 53,120 is 59.48%.
If you randomly select 13 days, their mean daily sales are greater than 53,120.00 (with this problem, a sample is introduced; therefore it is indicative of a chapter problem) (check figure: 19.22%).
STERR = STDEV.P / SQRT(13)