Question:
The monthly average sales of the Smiling Ninja Computer Company may be approximated to a normal distribution curve. It has a mean of $22,000 and a standard deviation of $3,300.
Drawing a curve for each question, calculate the proportions of the following:
a. The proportion of sales greater than $21,500 per month;
b. The proportion of sales less than $21,000 per month;
c. The proportion of sales between $22,500 and $24,500.
Note: Show all relevant workings and draw a normal distribution graph for each part.