Question

51. If total frequencies of three series are 50, 60
and 90 and their means are 12, 15 and 20
respectively, then the mean of their
composite series is
a) 16 b) 15.5 c) 16.5 d) 14.5
CA FOUNDATION DISCOVER | 1E​

Answer 1

Answer:

c

Step-by-step explanation:

50x12 + 60×15 + 90×20/ (50+60+90) = 3300/200 =16.5

Answer 2

Concept:

The three measurements of central tendency are the Mean, Median, and Mode. The mean of a set of data is its arithmetic average. This is calculated by averaging a data set's numbers and dividing the result by the set's total number of observations. When numbers are arranged in either ascending or descending order, the median is the value in the middle of the data set. The gap between the highest and lowest values in a data collection is known as the range, while the most frequent value in a data set is known as the mode.

Mean = sum of the numbers/ total number

Given:

If total frequencies of three series are 50, 60 and 90 and their means are 12, 15 and 20 respectively

Find:

The mean of their composite series is

Solution:

Sum of the series is = mean x frequency

Mean of thier composite series is =50x12 + 60×15 + 90×20/ (50+60+90)

                                                       = 3300/200 =16.5  

Therefore, the mean of the composite series is 16.5

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