Question

The number of CD's sold by Daniel's Discs for the last 6 days are given in the table.

Day Day 1 Day 2 Day 3 Day 4 Day 5 Day 6
CD's 15 10 10 10 18 15
Find the mean of the number of discs sold over the six day period.
Find the standard deviation of the number of discs sold over the six day period.
Complete your work in the space provided or upload a file that can display math symbols if your work requires it. Turn in all work associated with finding the mean and standard deviation.

Answer 1

Mean: 13

SD:
`√(10)`

Explanation:

To find the mean, you have to add up all of them and divide by the number of them. The sum is 30+30+18 or 78, and there are 6 so the mean is 78 / 6 = 13.

To find the standard deviation, we need to first find the distance from them to the mean. These are 2, 3, 3, 3, 5, and 2. Square these values to get 4, 9, 9, 9, 25, and 4. Now we have to take the mean of this, which is 8+27+25=35+25=60, so the mean is 10 and now we take the square root so the SD is
`√(10)`.