Probability of a Revenue Threshold

A retailer’s website purchases have an average order size of $100 and a standard deviation of $75. What is the probability of 10 orders generating over $1,250 in Revenue?

mean = $100.00
stdev = $75.00

avg_order_needed = $1250/10 = $125.00
standard_error = $75/sqrt(10) = $23.72
z-score = (125.00 – 100.00)/23.72 = 1.05

We are looking to solve for this shaded area under the curve.

upper_tail_post

Looking up on z-table for 1.05, the probability is 0.1469 or 14.7% of a obtaining $1,250 in Revenue from 10 random orders.