Calculate the mean from the following data:

Mid-value 10 20 30 40 50

Frequency 8 12 15 9 6

Open in App

Solution

Mid-Values (m) (f) fm

10
20
30
40
50 8
12
15
9
6 80
240
450
360
300

$Σ f$ =50 $Σ f m$ =1430

Calculating mean using direct method:

$X = \frac{Σ f m}{Σ f} o r, X = \frac{1430}{50} \Rightarrow X = 28.6$

Hence, mean of the above series is 28.6

Suggest Corrections

X	Below 10	10−20	20−30	30−40	40−50	50 and Above
Frequency	3	7	15	9	6	4

X	0−10	10−20	20−30	30−60	60−90
Frequency	5	9	20	12	4

Size	5−10	10−15	15−20	20−25	25−30	30−35	35−40	40−45	45−50
Frequency	6	10	18	30	15	12	10	6	4

Variable	0−10	10−20	20−30	30−40	40−50	50−60	60−70
Frequency	10	20	35	40	25	25	15

Class Interval	0-10	10-20	20-30	30-40	40-50	50-70
Frequency	7	10	8	20	32	28