RD Sharma Solutions for Class 10 Chapter 7 Statistics Exercise 7.2

RD Sharma Solutions Chapter 7 Statistics Exercise 7.2 Class 10 Maths

Chapter Name	RD Sharma Chapter 7 Statistics
Book Name	RD Sharma Mathematics for Class 10
Other Exercises	Exercise 7.1 Exercise 7.3 Exercise 7.4 Exercise 7.5 Exercise 7.6
Related Study	NCERT Solutions for Class 10 Maths

Exercise 7.2 Solutions

1. The number of telephone calls received at an exchange per interval for 250 successive one - minute intervals are given in the following frequency table : 

No. of calls (x)	0	1	2	3	4	5	6
No. of intervals (f)	15	24	29	46	54	43	39

Compute the mean number of calls per interval.

Solution

Let be assumed mean (A) = 3 

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

No. of heads per toss(x):	0	1	2	3	4	5
No. of tosses (f):	38	144	342	287	164	25

Solution

3. The following table gives the number of branches and number of plants in the garden of a school.

No. of branches (x):	2	3	4	5	6
No. of plants(f):	49	43	57	38	13

Calculate the average number of branches per plant.

Solution

4. The following table gives the number of children of 150 families in a village

No. of children(x):	0	1	2	3	4	5
No. of families(f):	10	21	55	42	15	7

Solution

5. The marks obtained out of 50, by 102 students in a physics test are given in the frequency table below:

Marks(x):	15	20	22	24	25	30	33	38	45
Frequency(f):	5	8	11	20	23	18	13	3	1

Find the average number of marks.

Solution

6. 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.

Solution

7. In the first proof reading of a book containing 300 pages the following distribution of misprints was obtained:

No. of misprints per page (x)	0	1	2	3	4	5
No. of pages(f);	154	95	36	9	5	1

Find the average number of misprints per page.

Solution

8. The following distribution gives the number of accidents met y 160 workers in a factory during a month.

No. of accidents(x):	0	1	2	3	4
No. of workers(f):	70	52	34	3	1

Find the average number of accidents per worker.

Solution

9. Find the mean from the following frequency distribution of marks at a test in statistics:

Marks(x):	5	10	15	20	25	30	35	40	45	50
No. of students(f):	15	50	80	76	72	45	39	9	8	6

Solution