A company's raw data sample of weekly salaries (in dollars) is shown below.
210 370 530 370 740 530
370 530 210 370 1140 210
A frequency distribution of this data set, based on a single-value grouping, is presented below with a third column showing the xf-values-the class midpoint (which here is the same as the class) times the class frequency.
|
Salary(x)
|
Frequency(f)
|
Salary*Frequency(xf)
|
|
210
|
3
|
630
|
|
370
|
4
|
1480
|
|
530
|
3
|
1590
|
|
740
|
1
|
740
|
|
1140
|
1
|
1140
|
(i). Use the raw data to obtain the sample standard deviation of the ungrouped data. Round your answer to two decimal places.
(ii). Use the grouped-data formula to obtain the sample standard deviation of the grouped data in the frequency distribution. Round your answer to two decimal places.
(iii). Compare your answers in parts (i) and (ii).