Question

For the following frequency distribution, what is the cumulative frequency for the class “30-under 40”?

Class interval	Frequency
10-under 20	20
20-under 30	16
30-under 40	30
40-under 50	18

20

36

66

30

83

2.

57	23	35	18	35
26	51	47	29	21
46	43	29	23	39
26	41	19	36	28
31	42	52	29	18
28	46	33	28	20

Class Interval	Frequencies
16 - under 23
23 - under 30
30 - under 37
37 - under 44
44 - under 51
51 - under 58
TOTAL

3. Assuming that the dataset 22, 5, -7, 11, 2, 11 is a sample, what is the sample standard deviation?

8.96

46.22

80.2

9.8

Answer 1

Solution :

1)

the cumulative frequency for the class “30-under 40" = 20 + 16 + 30 = 66

2)

Class Interval	Frequencies
16 - under 23	5
23 - under 30	9
30 - under 37	5
37 - under 44	5
44 - under 51	4
51 - under 58	2
Total	30

3)

Summary statistics:

Column	n	Std. dev.
Data	6	9.8115578

Sample standard deviation = 9.8