Q 1 – In a survey of 364 children aged 19-36 months, it was found that 91 liked to eat potato chips. If a child is selected at random, the probability that he/she does not like to eat potato chips is:
(a) 0.25
(b) 0.50
(c) 0.75
(d) 0.80
Ans. (c) 0.75
Q 2 – The probability of an impossible event is
(a) more than 1
(b) less than 1
(c) 1
(d) 0
Ans. (d) 0
Q 3 – In a sample study of 640 people, it was found that 512 people have a high school certificate. If a person is selected at random, the probability that the person has a high school certificate is:
(a) 0.5
(b) 0.6
(c) 0.7
(d) 0.8
Ans. (d) 0.8
Q 4 – A card is selected at random from a deck of 52 cards. The probability of its being a red face card is
Q 5 – In a series of 6 cricket matches, the number of runs scored by the captain of a team is 54, 32, 48, 55, 29, 35. So in the next match, the probability that he will cross the half-century is
(a) 0.33
(b) 0.24
(c) 0.35
(d) 0.48
Ans. (a) 0.33
Q 6 – The range of the data 25, 18, 20, 22, 16, 6, 17, 15, 12, 30, 32, 10, 19, 8, 11 and 20 is
(a) 10
(b) 15
(c) 18
(d) 26
Ans. (d) In a given data, maximum value = 32 and minimum value = 6
We know, range of the data = maximum value – minimum value
= 32 – 6 = 26
Hence, the range of the given data is 26.
Q 7 – When a die is thrown, the probability of getting an odd number less than 4 is
(d) 0
Q 8 – A and B throw a pair of dice. If A throws 9, then B’s chance of throwing a higher number is
Q 9 – A bag contains 16 cards bearing number 1, 2, 3 …., 16 respectively. One card is drawn at random. What is the probability that a number is divisible by 3?
Q 10 – In the class intervals 10-20, 20-30, the number 20 is included in
(a) 10-20
(b) 20-30
(c) Both the intervals
(d) None of these
Ans. (b) Since, the class interval 10-20 is the first interval of frequency distribution and 20-30 is the next one but the number 20 is present in both intervals. We know that, the presence of 20 in the interval 10-20 is not fully 100% while in the next interval 20-30, presence of it fully 100%.
Q 11 – The maximum probability of an event of a trial is:
(a) 0
(b) 1
(c) Lies between 0 and 1.
(d) -1
Ans. (b) 1
Q 12 – If m is the mid-point and l is the upper class limit of a class in a continuous frequency distribution, then lower class limit of the class is
(a) 2 m+l
(b) 2 m-l
(c) m-l
(d) m-2l
Ans. (b) Let x and y be the lower and upper class limit of a continuous frequency distribution.
Now, mid-point of a class = (x + y)/2 = m [given]
=> x + y = 2 m =x + l = 2m
[∴ y = l = upper class limit (given)]
=> x = 2 m-l
Hence, the lower class limit of the class is 2m – l.
Q 13 – The sum of the probabilities of all events of a trial is
(a) 1
(b) greater than 1
(c) less than 1
(d) between 0 and 1
Ans. (a) 1
Q 14 – The mean of 25 observations is 36. Out of these observations, if the mean of first 13 observations is 32 and that of the last 13 observations is 40, the 13th observation is
(a) 23
(b) 36
(c) 38
(d) 40
Ans. (b) Given, mean of 25 observations = 36
∴ Sum of 25 observations = 36 x 25 = 900 Now, the mean of first 13 observations = 32
∴ Sum of first 13 observations = 13 x 32 = 416 and the mean of last 13 observations = 40
∴ Sum of last 13 observations = 40 x 13 = 520
So, 13th observation = (Sum of last 13 observations + Sum of first 13 observations) – (Sum of 25 observations)
=(520 + 416)-900 = 936 – 900 = 36
Hence, the 13th observation is 36.
Q 15 – An unbiased dice is thrown. What is the probability of getting an even number or a multiple of 3?
Q 16 – A standard deck of 52 cards is shuffled. One card is drawn at random. The probability that the card is red or an ace is
Q 17 – The probability that bulbs selected randomly from the lot has life less than 900 h, is
Ans. (d) Total number of bulbs in a lot, n(S) = 80
Number of bulbs whose life time is less than 900 h, n(E) = 10 + 12 + 23 = 45
Probability that bulbs has life time less than 900 h =n(E)/n(S) = 45/80 = 9/16
Hence, the probability that bulb has life time less than 900 is 9/16.
Q 18 – A die is thrown 300 times and odd numbers are obtained 153 times. Then the probability of getting an even number is
Q 19 – Two coins are tossed 1000 times and the outcomes are recorded as below:
| No. of heads | 2 | 1 | 0 |
| Frequency | 200 | 550 | 250 |
The probability of getting at the most one head is:
Q 20 – In a football match, a player hits 8 goals out of 60 balls. Find the probability that the player did not hit the goal.
Q 21 – What is the probability that a leap year has 53 Sundays?
