Chapter 15 Statistics Ex 15.4

Rajasthan Board RBSE Class 9 Maths Solutions Chapter 15 Statistics Ex 15.4

Question 1.
The following number of goals were scored by a football team in a series of 10 matches: 2, 3, 4, 5, 0, 1, 3, 3, 4, 3
Find the mean, median and mode of these scores.
Solution.
The number of goals scored by a football team in a series of 10 matches are as under 2, 3, 4, 5, 0, 1, 3, 3, 4, 3
(i) Mean

(ii) Median: Arranging the given data in ascending order, we have 0, 1, 2, 3, 3, 3, 3, 4, 4, 5
Here, n = 10 which is even, so there will be two median class

(iii) Mode: The number 3 occurs most frequently in the data i.e. 4 times. Hence, Mode = 3

Question 2.
In a Mathematics test given by 15 students, the following marks (out of 100) are recorded: 41, 39, 48, 52, 46, 62, 54, 40, 96, 52, 98, 40, 42, 52, 60
Find the mean, median and mode of these data.
Solution:
(i) Mean

Hence, mean of the given data is 54.8.
(ii) Median: Arranging the given data in the ascending order,
we have 39, 40, 40, 41, 42, 46, 48, 52, 52, 52, 54, 60, 62, 96, 98
Here, n = 15 which is odd, so their will be only one median class

(iii) Here, the mark 52 occurred most frequently i.e. 3 times.
Hence, Mode = 52.

Question 3.
The following observations have been arranged in ascending order. If the median of the data is 63. Find the value of x.
29, 32, 48, 50, x, x + 2, 72, 78, 84, 95.
Solution:
Here, number of observations = 10 (even)

Question 4.
Find the mode of 14, 25, 14, 28, 18, 17, 18, 14, 23, 22, 14, 18.
Solution.
We find that the observation 14 occurs frequently maximum number of times i.e. 4 times. Hence, mode is 14.

Question 5.
Find the mean salary of 60 workers of a factory from the following table:

Solution.
Here, we will find mean salary of 60 workers of a factory by direct method.

Hence, mean salary of 60 workers of a factory is Rs 5083.33.