Question

A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent.




Number of days



0 − 6



6 − 10



10 − 14



14 − 20



20 − 28



28 − 38



38 − 40





Number of students



11



10



7



4



4



3



1

Answer 1

Answer:

Mean = 12.48  

Step-by-step explanation:

Since the class interval is not same, we need to find the mean of the group of data by direct method.  

The mean of data from direct method = ∑(f * x)/∑( f)

f – Frequency

x – Class average = (lower bound + upper bound) / 2  

Let us represent all data in the table below as

Number  number of      Class fx

of days students (f) average (x)

0 – 6     11   (0+6)/2 = 3 33

6 – 10     10   8           80

10 – 14       7   12           84

14 – 20     4   17           68

20 – 28     4   24             96

28 – 38      3   33           99

38 – 40      1     39           39

∑(fx) = 499

∑(f) = 40

Mean = 499/40 = 12.48  

Answer 2

Answer:

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Here is the process of both direct mwthod and assume mean method

As class size are different so step deviation method vould not be used

Step-by-step explanation:

First meke the columns and go on the process inthe attachment