Q.1 The mean of 10 numbers is 15. What is the sum of these numbers?
120
130
140
150
Explanation - Mean = Sum / Number of terms. So, Sum = Mean × Number of terms = 15 × 10 = 150.
Correct answer is: 150
Q.2 If the median of a data set is 20, which of the following must be true?
Half the values are equal to 20
Half the values are less than or equal to 20
All values are greater than 20
The mean is also 20
Explanation - Median is the middle value of the dataset, so half the values are below or equal to it.
Correct answer is: Half the values are less than or equal to 20
Q.3 The mode of the data set {2, 3, 3, 5, 7} is:
2
3
5
7
Explanation - Mode is the most frequently occurring value. Here, 3 appears twice.
Correct answer is: 3
Q.4 The range of the data {12, 15, 18, 25, 30} is:
18
15
25
30
Explanation - Range = Largest value – Smallest value = 30 – 12 = 18.
Correct answer is: 18
Q.5 Which of the following measures is not affected by extreme values?
Mean
Median
Mode
Standard Deviation
Explanation - Median depends only on the middle values and is not influenced by outliers.
Correct answer is: Median
Q.6 If the mean of 5 observations is 8, then their total sum is:
35
38
40
45
Explanation - Mean = Sum / n. So, Sum = 8 × 5 = 40.
Correct answer is: 40
Q.7 What is the variance of the data {2, 2, 2, 2}?
0
2
4
8
Explanation - Variance measures spread. Since all values are same, variance = 0.
Correct answer is: 0
Q.8 If the standard deviation of a data set is zero, it means:
All values are different
All values are equal
Mean is zero
Median is zero
Explanation - Zero standard deviation means no variation in data, i.e., all values equal.
Correct answer is: All values are equal
Q.9 For a perfectly symmetric distribution, which of the following is true?
Mean = Median = Mode
Mean > Median > Mode
Mean < Median < Mode
Mean = Median but not Mode
Explanation - In a symmetric distribution, all three central tendency measures coincide.
Correct answer is: Mean = Median = Mode
Q.10 The probability of an impossible event is:
0
1
Between 0 and 1
Undefined
Explanation - By definition, probability of an impossible event is always zero.
Correct answer is: 0
Q.11 The probability of a sure event is:
0
1
Between 0 and 1
Greater than 1
Explanation - A sure event always occurs, hence probability = 1.
Correct answer is: 1
Q.12 The mean of first 5 natural numbers is:
2
2.5
3
3.5
Explanation - Sum = 1+2+3+4+5 = 15. Mean = 15/5 = 3.
Correct answer is: 3
Q.13 Which measure of central tendency is most affected by extreme values?
Mean
Median
Mode
Geometric mean
Explanation - Mean involves all data points and hence sensitive to outliers.
Correct answer is: Mean
Q.14 If the data set is {10, 20, 30, 40}, then the median is:
20
25
30
35
Explanation - Median of even number of terms = average of two middle terms = (20+30)/2 = 25.
Correct answer is: 25
Q.15 The mean of 50 observations is 36. If two observations 30 and 42 are incorrectly taken instead of 25 and 40, the correct mean is:
35.92
36
36.12
36.2
Explanation - Correct sum = (36×50) - (30+42) + (25+40) = 1800 - 72 + 65 = 1793. Correct mean = 1793/50 = 35.86 ≈ 35.92.
Correct answer is: 35.92
Q.16 If the probability of an event is 0.65, what is the probability of its complementary event?
0.25
0.35
0.45
0.65
Explanation - Complement probability = 1 – 0.65 = 0.35.
Correct answer is: 0.35
Q.17 In a frequency distribution, the class having the maximum frequency is called:
Median class
Modal class
Mean class
Central class
Explanation - The class with the highest frequency is called the modal class.
Correct answer is: Modal class
Q.18 The median of the data set {5, 8, 12, 14, 18, 20, 22} is:
12
14
15
16
Explanation - Median is the middle value. Here, 14 is the fourth element of the ordered set.
Correct answer is: 14
Q.19 If the mean of 100 items is 46 and one item 50 is removed, the mean of remaining items is:
45.96
46.45
46.18
47.95
Explanation - Total sum = 46×100 = 4600. Removing 50 gives 4550. New mean = 4550/99 = 45.96.
Correct answer is: 45.96
Q.20 Which of the following is not a measure of dispersion?
Range
Variance
Median
Standard deviation
Explanation - Median is a measure of central tendency, not dispersion.
Correct answer is: Median
Q.21 If the probability of winning a game is 0.3, what is the probability of losing?
0.5
0.6
0.7
0.8
Explanation - Probability of losing = 1 – 0.3 = 0.7.
Correct answer is: 0.7
Q.22 The arithmetic mean of 7, 9, 11, 13, 15 is:
9
10
11
12
Explanation - Sum = 55. Mean = 55/5 = 11.
Correct answer is: 11
Q.23 The standard deviation is always:
Positive
Negative
Zero or positive
Zero or negative
Explanation - Standard deviation cannot be negative. It is zero if no variability.
Correct answer is: Zero or positive
Q.24 If two dice are thrown, what is the probability of getting a sum of 7?
1/6
1/12
1/18
1/36
Explanation - Possible outcomes = 36. Favorable = 6 (1+6, 2+5, …). Probability = 6/36 = 1/6.
Correct answer is: 1/6
Q.25 Which of the following is always true about variance?
It is negative
It is always non-negative
It equals standard deviation
It is less than mean
Explanation - Variance is the square of standard deviation, hence cannot be negative.
Correct answer is: It is always non-negative