Question

Grace is looking at a report of her monthly cell-phone usage for the last year to determine if she needs to upgrade her plan. The list represents the approximate number of megabytes of data Grace used each month.

700, 735, 680, 890, 755, 740, 670, 785, 805, 1050, 820, 750


What is the standard deviation of the data? Round to the nearest whole number.


A. 65

B. 75

C. 100

D. 130

Answer 1

C is your answer :) have a good day

Answer 2

Standard deviation of the data set is option C. 100.

Explanation:

To find the standard deviation, we first have to calculate the mean (average) of the numbers.

Mean = addition of total value of data set / total number of values.

= 700+ 735+ 680+ 890+ 755+ 740+ 670+ 785+ 805+ 1050+ 820+ 750/ 12

= 9380 / 12 = 781.66 rounded to 782.

Mean = 782.

Next, we take each number and subtract the mean, taking the result and squaring it.

For this we get:

6724, 2209, 10404, 11664, 729, 1764, 12544, 9, 529, 71824, 1444, 1024.

Now we add all of these values and take the average by dividing the sum by 12.

Doing this we get 120868/12 = 10072.

The last step is the take the square root of that number to get the standard deviation. The final result is 100.