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, 750What is the standard deviation of the data? Round to the nearest whole number

Answer 1

The answer for this one is 100

Answer 2

100

Explanation:

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

Total number of observations = 12

`Mean = \frac{\text{Sum of all observations}}{\text{Total no. of observations}}`

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

`Mean = 781.666`

So,
`\bar{x}=781.666`

Standard deviation =
`\sigma = \sqrt{\frac{\sum(x_i-{x})^2}{n}}`

So,

`\sigma = 100.36`

So, the standard deviation of the data round to the nearest whole number is 100