ly short cut method to find arithmetic mean in each of the following (17 - 26):
2. Class-Interval 0-30 30–60 60-90 90-120 120-150 150–180
Frequency 12 18 22 24 17 7
Answers
Arithmetic mean = 86.1
Step-by-step explanation:
We are given the following frequency distribution data below;
Class Interval Frequency (f) X d = X - A
0 - 30 12 15 15 - 75 = -60 -720
30 - 60 18 45 45 - 75 = -30 - 540
60 - 90 22 75 75 - 75 = 0 0
90 - 120 24 105 105 - 75 = 30 720
120 - 150 17 135 135 - 75 = 60 1020
150 - 180 7 165 165 - 75 = 90 630
Total 100 1110
Here, A = assumed mean. So, we let A = 75 here.
Now, the short-cut method of the arithmetic mean is given by the following formula;
Mean =
Here, = 1110 and = 100
So, Arithmetic Mean =
= 75 + 11.1 = 86.1
Therefore, arithmetic mean of the data using short cut method is 86.1.