RS Aggarwal Class 7 Mathematics Twenty One Chapter Collection and Organisation of Data (Mean, Median and Mode) Exercise 21C Solution

RS Aggarwal Class 7 Mathematics Twenty One Chapter Collection and Organisation of Data (Mean, Median and Mode) Exercise 21C Solution

EXERCISE 21C

(1) Find the mode of the data:

(i) 10, 8, 4, 7, 8, 11, 15, 8, 6, 8

Ans: Here, 8 occurs most frequently. Hence, the mode of the data is 8.

(ii) 27, 23, 39, 18, 27, 21, 27, 27, 40, 36, 27

Ans: Here, 27 occurs most frequently. Hence, the mode of the data is 27.

(2) The ages (in years) of 11 cricket players are given below:

28, 34, 32, 41, 36, 32, 32, 38, 32, 40, 31

Mode is the value of the variable that occurs most frequently.

Here, 32 occurs maximum number of times.

Hence, 32 is the mode of the ages.

Find the mode of the ages.

(3) Daily wages of 45 workers in a factory are given below:

Daily wages (in Rs)	300	375	450	525	600
Number of workers	6	8	9	12	10

Find the median and mean. Using empirical formula, calculate its mode.

Daily wages (in Rs)(xi)	Number of workers  (fi)	Cumulative frequency	(fi × xi)
300	6	6	1800
375	8	14	3000
450	9	23	4050
525	12	35	6300
600	10	45	6000

(4) The following table shows the marks obtained by 41 students of a class.

Marks obtained	15	17	20	22	25	30
Number of students	2	5	10	12	8	4

Find the median and mean marks. Using empirical formula, calculate its mode.

Marks obtained(xi)	Number of students (fi)	Cumulative frequency	(fi × xi)
15	2	2	30
17	5	7	85
20	10	17	200
22	12	29	264
25	8	8	200
30	4∑fi = 41	4	120∑(fi × xi) = 899

(5) The following table shows the weight of 12 players:

Weight (in kg)	48	50	52	54	58
Number of players	4	3	2	2	1

Find the median and mean weights. Using empirical formula, calculate its mode.

Weight (in kg)(xi)	Number of players  (fi)	Cumulative frequency	(fi × xi)
48	4	4	192
50	3	7	150
52	2	9	104
54	2	11	108
58	1∑fi = 12	12	58∑fi × xi = 612