The number of students absent in a class were recorded every day for 120 days and the information is given in the following frequency table:
No. of students absent ($x$):01234567
No. of days ($f$):141050341542
Find the mean number of students absents per day.

Given:

The number of students absent in a class were recorded every day for 120 days and the information is given in the frequency table

To do:

We have to find the mean number of students absents per day.

Solution:

Let the assumed mean be $A=3$

Number of students absent ($x_i$)Number of days ($f_i$)

$d_i = x_i -A$

$A = 3$ 

$f_i \times\ d_i$
01$-3$$-3$
14$-2$$-8$
210$-1$$-10$
3- $A$5000
434134
515230
64312
7248
Total $\sum{f_i}=120$$\sum{f_id_i}=63$

 We know that,

Mean $=A+\frac{\sum{f_id_i}}{\sum{f_i}}$  

Therefore, 

Mean $=3+\frac{63}{120}$

$=3+0.525$

$=3.525$

The mean number of students per day is $3.53$.

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Updated on: 10-Oct-2022

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