Question

The following table is the frequency distribution for the amount 'screen time' (in hours) had each day by 50 employees at a large, multinational corporation. Screen time is loosely defined as time spent using a computer, tablet, gaming console, television, or smart phone.

Screen Time Freq

0

≤

x

<

6

0

≤

x

<

6

28

6

≤

x

<

12

6

≤

x

<

12

20

12

≤

x

<

18

12

≤

x

<

18

2

Are these population or sample data?

Use the table above to make the following calculations. Round solutions to three decimal places, if necessary.

Mean =

Variance =

Standard Deviation =

Answer 1

These are sample data since these represent 50 employees at a large, multinational corporation.

0 x 6     28

6 x 12     20

12 x 18 2

From the given data, the following Tableis calculated:

Class	Mid value (x)	Frequency (f)	x f	x2 f
0 - 6	3	28	84	252
6 - 12	9	20	180	1620
12 - 18	15	2	30	450
Total =		n =50

Mean () is given by:

Variance (s²) is given by:

Standard Deviation (s0 is given by: