## Chapter 7 Statistics R.D. Sharma Solutions for Class 10th Math Exercise 7.1

1. Calculate the mean for the following distribution:
x: 5 6 7 8 9

f: 4 8 14 11 3Â Â

**Solution**

2. Find the mean of the following data:

x: 19 21 23 25 27 29 31

f.Â 13 15 16 18 16 15 1

x: 19 21 23 25 27 29 31

f.Â 13 15 16 18 16 15 1

**Solution**

3. If the mean of the following data is 20.6. Find the value of p.

x: 10 15 p 25 35

f:Â 3 10 25 7 5

**Solution**

4. If the mean of the following data is 15, find p.

x: 5 10 15 20 25

f: 6 p 6 10 5

**Solution**

5. Find the value of p for the following distribution whose mean is 16.6

x: 8Â 12Â 15Â pÂ 20Â 25 30f. 12 16 20 24 16 8 4

**Solution**

x: 5 8 10 12Â p 20 25

f. 2 5 8 22 7 4 2

**Solution**

7. Find the missing frequency (p) for the following distribution whose mean is 7.68.

x: 3 5 7 9 11 13

f: 6 8 15 p 8 4Â

**Solution**

8.Â The following table gives the number of boys of a particular age in a class of 40 students.

Calculate the mean age of the studentsÂ

Age (in years): 15 16 17 18 19 20

No. of students: 3Â 8Â Â 10 10Â 5Â 4

**Solution**Â

9. Candidates of four schools appear in a mathematics test. The data were as follows:

Â

If the average score of the candidates of all the four schools is 66, find the number of

candidates that appeared from school III.

candidates that appeared from school III.

**Solution**

10. Five coins were simultaneously tossed 1000 times and at each toss the number of heads

were observed. The number of tosses during which 0, 1, 2, 3, 4 and 5 heads were obtained

are shown in the table below. Find the mean number of heads per toss.

were observed. The number of tosses during which 0, 1, 2, 3, 4 and 5 heads were obtained

are shown in the table below. Find the mean number of heads per toss.

**Solution**

11. The arithmetic mean of the following data is 14. Find the value of k

x

_{i}Â : 5 10 15 20 25
f

_{i}Â : 7 k 8 4 5**Solution**

12. The arithmetic mean of the following data is 25, find the value of k.

x

_{i}Â :Â 5 15 25 35 45

f

_{i}Â : 3 k 3 6 2Â

**Solution**

13.Â If the mean of the following data is 18.75. Find the value of p.

x

_{i}Â : 10 15 p 25 30

f

_{i}Â : 5 10 7 8 2

**Solution**

14. Find the value of p, if the mean of the following distribution is 20.

x: 15 17 19 20+p 23

f: 2 3 4 5p 6Â

**Solution**

15.Â Find the missing frequencies in the following frequency distribution if it is known that the

mean of the distribution is 50.

x: 10 30 50 70 90

f:Â 17 f

_{1}Â 32 f

_{2}Â 19

**Solution**