Ncert – Class 10 – Statistics– Hots Question

Question 1

A bag contains a red ball, a blue ball and a yellow ball, all the balls being of the same size.
Kritika takes out a ball from the bag without looking into it. What is the probability that she
takes out the
(i) yellow ball?
(ii) red ball?
(iii) blue ball?

Solution

The number of possible outcomes = Number of balls in the bag = n(S) = 3.
(i) The number of outcomes favourable to the event Y = n(Y) = 1.
So, P(Y) = n(Y)/n(S) =1/3Similarly,
(ii) P(R) = 1/3and
(iii) P(B) = ⅓

Question 2

A box contains 80 discs which are numbered from 1 to 80. If one disc is drawn at random
from the box, find the probability that it bears a perfect square number.

Solution

Total number of outcomes = 80
Perfect square numbers from 1 to 80 = 1 ,4, 9, 16, 25, 36, 49, 64
Therefore, favourable outcomes = 8
Probability of getting a perfect square number = 8/80 = 1/10.

Question 3

The median of the following data is 525. Find the missing frequency ‘x’
Find the modal height.

Solution

n=100, 76+x+y=100, x+y=24, given median is 525. Median class 500-600 I=500, h=100,
f=20, cf=36+x

525= 500+50−(36+𝑥)/ 20 ∗ 100 Simplifying we get x=9 and y=15

Question 4

Find mode of the following distribution

Solution

46.11

Question 5

Find the mean of the following data

Solution

=>52.5

Question 6

If the mean of the following data is 18.75. find the value of P.

Solution

P=20

Question 7

Determine the missing frequency x, from the following data, hwn Mode is 67

Solution

x=8

Question 8

The following data gives the information observed life times (in hours) of 225 electrical components. Determine the modal life times of the components.

Solution

=65.625 hours

Question 9

Find the median of the following data:

Solution

76.36

Question 10

The median of the distribution given below is 14.4. Find the values of x and y, if
the sum of all the frequencies is 20.

Solution

X=4 and Y=6