Less than type Cumulative frequency table for grouped data calculator

SolutionHelp

1. Calculate the mean and standard deviation for the following distribution

X	6	7	8	9	10	11	12
f	3	6	9	13	8	5	4

2. Calculate the mean and standard deviation for the following distribution

Class	50-55	45-50	40-45	35-40	30-35	35-30	20-25
f	25	30	40	45	80	110	170

Example

1. Calculate Less than type Cumulative frequency table from the following grouped data
Class Frequency
10 - 20 15
20 - 30 25
30 - 40 20
40 - 50 12
50 - 60 8
60 - 70 5
70 - 80 3

Solution:

Class	Frequency
10 - 20	15
20 - 30	25
30 - 40	20
40 - 50	12
50 - 60	8
60 - 70	5
70 - 80	3

Less than cumulative frequency can be obtained by adding to the other frequencies.

Class	Frequency	Less than type	Cumulative Frequency
10 - 20	15	Less than 20	15
20 - 30	25	Less than 30	40 (= 15 + 25)
30 - 40	20	Less than 40	60 (= 40 + 20)
40 - 50	12	Less than 50	72 (= 60 + 12)
50 - 60	8	Less than 60	80 (= 72 + 8)
60 - 70	5	Less than 70	85 (= 80 + 5)
70 - 80	3	Less than 80	88 (= 85 + 3)