The number of students absent in a class were recorded for $120$ days and the information is given in the following frequency table:
No. of students
absent ( $x$ ) $0$ $1$ $2$ $3$ $4$ $5$ $6$ $7$
No. of days ( $f$ ) $1$ $4$ $10$ $50$ $34$ $15$ $4$ $2$
Find the mean number of students absent per day.

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Solution

No. of students
absent (x) No. of days (f) fx
0 1 0
1 4 4
2 10 20
3 50 150
4 34 136
5 15 75
6 4 24
7 2 14
$Σ f = 1 + 4 + 10 + 50 + 34 + 15 + 4 + 2 = 120$ $Σ f x = 0 + 4 + 20 + 150 + 136 + 75 + 24 + 14 = 423$
Mean number of students absent per day $(¯ x) = \frac{Σ f x}{Σ f} = \frac{423}{120} = 3.525$

Hence, the mean number of students absent per day is $3.525$ .

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Similar questions

Q. 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):	0	1	2	3	4	5	6	7
No. of days (f):	1	4	10	50	34	15	4	2

Find the mean number of students absent per day.

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): 0 1 2 3 4 5 6 7
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Find the mean number of students absent per day.

Q. 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

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.

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Q. The number of students absent in a school was recorded every day for

147

days and the raw data was presented in the form of the following frequency table.

No. of students absent:	5	6	7	8	9	10	11	12	13	15	18	20
No. of days:	1	5	11	14	16	13	10	70	4	1	1	1

Obtain the median and describe what information it conveys.

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No. of students absent ( $x$ )	$0$	$1$	$2$	$3$	$4$	$5$	$6$	$7$
No. of days ( $f$ )	$1$	$4$	$10$	$50$	$34$	$15$	$4$	$2$

No. of students absent (x)	No. of days (f)	fx
0	1	0
1	4	4
2	10	20
3	50	150
4	34	136
5	15	75
6	4	24
7	2	14
	$Σ f = 1 + 4 + 10 + 50 + 34 + 15 + 4 + 2 = 120$	$Σ f x = 0 + 4 + 20 + 150 + 136 + 75 + 24 + 14 = 423$

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

No. of studentsabsent (x) No. of days (f) fx 0 1 0 1 4 4 2 10 20 3 50 150 4 34 136 5 15 756 4 24 7 2 14 Σf=1+4+10+50+34+15+4+2 =120 Σfx=0+4+20+150+136+75+24+14 =423 Mean number of students absent per day (¯x)=ΣfxΣf=423120=3.525Hence, the mean number of students absent per day is 3.525.