For a particular year following is the distribution of ages (in years) of primary school teachers in a district

Age (in years)

15-20

20-25

25-30

30-35

35-40

40-45

45-50

No. of teachers

10

30

50

50

30

6

4

1)      1) Write the lower limit of first class interval

2)      2) Determine the class limits of the fourth class interval

3)      3) Find the class mark of the class 45-50

4)  Determine the class-size

1) The lower limit of first class interval=15.

2) The class limits of the fourth class interval=30-35

3) Class mark of the class 45-50 is 

4) Class-size:The class size of any class interval is the difference between the lower and upper limit of the given class interval and the minimum class size is the smallest class size.

AgeNo. of teachersClass size

15– 20

20 – 25

25 – 30

30– 35

35– 40

40-45

45-50

10

30

50

50

30

0

4

20-15=5

25-20=5

30-25=5

35-30=5

40-35=5

45-40=5

50-45=5

 

In the given data, it can be observed that the class size is 5 for each interval.


 

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