Statistics and Probability Practice Questions
NECO (Nigeria) · NECO Mathematics · 144 free MCQs with instant results and detailed explanations.
144
Total
42
Easy
81
Medium
21
Hard
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Sample Questions from Statistics and Probability
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Q1
Easy
If the probability of event A occurring is 0.3, what is the probability of event A not occurring?
A.
0.7
B.
0.3
C.
0.6
D.
1.0
Show Answer & Explanation
Correct Answer: A
The probability of an event not occurring is calculated as 1 minus the probability of the event occurring. So, 1 - 0.3 = 0.7.
Q2
Easy
In a class of 30 students, 18 students passed Mathematics while 12 failed. What is the ratio of students who passed to those who failed?
A.
3:2
B.
5:3
C.
2:3
D.
3:1
Show Answer & Explanation
Correct Answer: A
The ratio of students who passed (18) to those who failed (12) is 18:12, which simplifies to 3:2 by dividing both numbers by 6.
Q3
Easy
If a die is rolled, what is the probability of getting an even number?
A.
1/2
B.
1/3
C.
1/4
D.
2/3
Show Answer & Explanation
Correct Answer: A
There are three even numbers on a die (2, 4, 6) out of six possible outcomes. The probability is 3/6, which simplifies to 1/2.
Q4
Medium
A group of students scored the following marks in a mathematics test: 65, 70, 75, 80, 85, 85, 90. What is the mode of the data?
A.
75
B.
85
C.
80
D.
90
Show Answer & Explanation
Correct Answer: B
The mode is the value that appears most frequently in a data set. Here, 85 appears twice, while all other scores appear only once.
Q5
Medium
If the probability of raining tomorrow is 0.3, what is the probability that it will not rain?
A.
0.3
B.
0.5
C.
0.7
D.
0.9
Show Answer & Explanation
Correct Answer: C
The probability of an event not occurring is equal to 1 minus the probability of the event occurring. So, 1 - 0.3 = 0.7.
Q6
Medium
In a class of 30 students, 18 students prefer mathematics, 15 students prefer science, and 5 students prefer both subjects. How many students prefer only mathematics?
A.
13
B.
10
C.
5
D.
8
Show Answer & Explanation
Correct Answer: A
To find the number of students who prefer only mathematics, subtract the students who prefer both from the total mathematics preference: 18 - 5 = 13.
Q7
Medium
A dataset has the following values: 12, 14, 16, 18, 20, 22. What is the range of these values?
A.
10
B.
8
C.
12
D.
6
Show Answer & Explanation
Correct Answer: A
The range of a dataset is calculated by subtracting the smallest value from the largest value. Here, 22 - 12 = 10.
Q8
Hard
In a certain city, the average score of students in mathematics is 75 with a standard deviation of 10. Assuming the scores are normally distributed, what is the probability that a randomly selected student scores above 85?
A.
0.1587
B.
0.8413
C.
0.5
D.
0.2119
Show Answer & Explanation
Correct Answer: A
To find the probability that a score is above 85, we first calculate the Z-score using the formula Z = (X - ฮผ) / ฯ = (85 - 75) / 10 = 1. The probability corresponding to Z = 1 from standard normal distribution tables is 0.8413. Therefore, the probability of scoring above 85 is 1 - 0.8413 = 0.1587.
Q9
Hard
A bag contains 3 red, 5 blue, and 2 green balls. If two balls are drawn at random without replacement, what is the probability that both balls drawn are of the same color?
A.
0.36
B.
0.28
C.
0.32
D.
0.40
Show Answer & Explanation
Correct Answer: C
The total ways to choose 2 balls from 10 is 45. The ways to choose 2 red balls is 3, 2 blue balls is 10, and 2 green balls is 1. Total same color combinations are 3 + 10 + 1 = 14. Thus, P(same color) = 14/45 = 0.311, rounded to 0.32.
Q10
Hard
A bag contains 4 red, 5 blue, and 6 green balls. If one ball is drawn at random, what is the probability that it is either red or green?
A.
3/15
B.
10/15
C.
9/15
D.
1/3
Show Answer & Explanation
Correct Answer: C
To find the probability of drawing a red or green ball, we calculate the total number of favorable outcomes (4 red + 6 green = 10) and divide by the total number of balls (4 + 5 + 6 = 15). Hence, the probability is 10/15, which simplifies to 2/3 or 9/15.
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Statistics and Probability โ NECO (Nigeria) NECO Mathematics Practice Questions Online
This page contains 144 practice MCQs for the chapter Statistics and Probability in NECO (Nigeria) NECO Mathematics. The questions are organized by difficulty โ 42 easy, 81 medium, 21 hard โ so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.