Statistics and Probability Generix Content - Statistics and Probability
"Statistics and Probability" question number distribution across years
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WAEC questions for "Mathematics :: Statistics and Probability"
Q1

 Number of pets 0 1 2 3 4 Number of students 8 4 5 10 3
The table shows the number of pets kept by 30 students in a class. If a student is picked at random from the class, what is the probability that he/she kept more than one pet?

A

1/5

B

2/5

C

3/5

D

4/5

E
Q2

What percentage of the students had marks ranging from 35 to 50?

A

551/3 %

B

60%

C

65%

D

662/3%

E
Q3

The mean age of R men in a club is 50years. Two men, aged 55 and 63, left the club and the mean age reduced by 1 year. Find the value of R.

A

18

B

20

C

22

D

28

E
Q4

In an athletics competition, the probability that an athlete wins a 100m race is 1/8 and the probability that he wins in high jump is 1/4 . What is the probability that he wins only one of the event?

A

3/32

B

3/16

C

7/32

D

5/16

E
Q5

In an examination, Kofi scored x% in Physics, 50% in Chemistry and 70% in Biology. If his mean score for the three subjects was 55%, find x.

A

40

B

45

C

55

D

60

E
Q6

What is the median of the following scores: 22, 41, 35, 63, 82, 74?

A

82

B

52

C

49

D

22

E
Q7

A box contains black, white and red identical balls. The probability of picking a black ball at random from the bax is 3/10 and the probability of picking a white ball at random is 2/5. If there are 30 balls in the box, how many of them are red?

A

3

B

7

C

9

D

12

E
Q8

How many students graduated from the Science Department?

A

840

B

864

C

920

D

960

E
Q9

If a student is picked at random from the four Departments, what is the probability that he is not from the Education Department?

A

3/10

B

2/9

C

5/18

D

7/10

E
Q10

The graph below shows the pattern of a town in a year. What is the average monthly rainfall?

A

2.70cm

B

2.71cm

C

2.72cm

D

2.78cm

E
Q11

If a number is selected at random from set B, what is the probability that the number is prime?

A

1

B

3/4

C

1/2

D

1/4

E
Q12

If a number is picked at random from each of the two sets, what is the probability that their product is odd?

A

1

B

3/4

C

1/4

D

0

E
Q13

If a number is picked at random from each of the two sets, what is the probability that their differences is 6 or 7?

A

1/256

B

1/16

C

1/8

D

1/2

E
Q14

Find the mean deviation of these numbers: 10,12,14,15,17,19.

A

2.5

B

2.6

C

2.7

D

2.8

E
Q15

The table gives the distribution of the marks of a number of students ina test.

 Mark 1 2 3 4 5 6 Frequency 5 3 6 4 2 5
Find the mode of the distribution.

A

2

B

3

C

5

D

6

E
Q16

If the probability of an event occurring is x, what is the probability of the event not occurring?

A

1 - x

B

x - 1

C

0

D

1/x

E
Q17

what is the mean age?

A

4.46 years

B

3.35 years

C

3.30 years

D

3.00 years

E
Q18

What is the mean of the distribution?

A

3.5years

B

3.0years

C

2.5years

D

2.0 years

E
Q19

Divide the sum of 8, 6, 7, 2,0, 4, 7, 2, 3 by their mean

A

9

B

8

C

7

D

6

E
Q20

A fair coin is tossed three times. Find the probability of getting two heads and one tail

A

1/2

B

3/8

C

1/4

D

1/8

E
Q21

The ratio of boys to girls in a class is 5:3. Find the probability of selecting at random, a girl from the class.

A

1/8

B

1/3

C

3/8

D

3/5

E
Q22

How many purpils took the test?

A

36

B

38

C

39

D

40

E
Q23

If the pass mark was 4, what percentage of the pupils failed the test?

A

20.0%

B

37.5%

C

62.5%

D

80.0%

E
Q24

Which of the following is not a measure of central tendency?

A

mean

B

mode

C

range

D

median

E
Q25

The teperature in a chemical plant was -5°C at 2.00 am. The temperature fell by 6°C and then rose again by 7°C. What was the final temperature?

A

-6°C

B

-4°C

C

4°C

D

8°C

E
Q26

A fair dice is tossed once, what is the probability of obtaining neither 5 nor 2?

A

5/6

B

2/3

C

1/2

D

1/6

E
Q27

The probability that John and james pass an examination are 3/4 and 3/5 repectively. Find the probability of both boys failing the examination.

A

1/10

B

3/10

C

9/20

D

11/20

E
Q28

Find the mean of the numbers 1, 3, 4, 8, 8, 4 and 7

A

4

B

5

C

6

D

7

E
Q29

Find the total number of students in the class

A

27

B

31

C

33

D

34

E
Q30

How many students received ₦300 or ₦500 for a week?

A

7

B

11

C

18

D

19

E
Q31

There are m boys and 12 girls in a class. What is the probability of selecting at random a girl from the class?

A

m/12

B

12/m

C

12/m + 12

D

m/m+12

E
Q32

Find, correct to two decimal places, the mean of 9, 13, 16, 17, 19, 23, 24

A

23.00

B

17.29

C

16.50

D

16.33

E
Q33

Find the mean deviation of 6,7,8,9,10

A

1.2

B

1.5

C

2

D

8

E
Q34

Find the average of the first four prime numbers greater than 10.

A

20

B

19

C

17

D

15

E
Q35

What is the median marks?

A

1

B

2

C

3

D

4

E
Q36

What is the probability of selecting a student from the group that scored 2 or 3?

A

1/11

B

5/25

C

7/22

D

6/11

E
Q37

A bag contains 3red and 2 white identical balls. If 2 balls are picked at random from the bag, one after the other and with replacement, find the probability that they are of different colours.

A

36/625

B

16/625

C

12/25

D

13/25

E
Q38

The mode of the distribution is

A

3

B

5

C

8

D

18

E
Q39

Find the median of the distribution

A

1

B

2

C

3

D

4

E
Q40

How many pupils scored at least 2 marks?

A

12

B

23

C

37

D

49

E
Q41

Out of 60 member of an association, 15 are Doctors and 9 are Lawyers. If a member is selected at random from the Association. what is the probability that the member is neither a Doctor nor a Lawyer?

A

3/5

B

9/10

C

3/20

D

1/4

E
Q42

The possibilities of a boy passing English and Mathematics tests are x and y respectively. Find the probability of the boy failing both tests

A

1 - (x - y) + xy

B

1 - (x + y) - xy

C

1 - (x + y) + xy

D

1 - (x - y) - xy

E
Q43

Which of the following is not a measure of dispersion?

A

Range

B

Mean Deviation

C

Mean

D

Standard Deviation

E
Q44

The variance of a given distribution is 25. What is the standard deviation?

A

125

B

75

C

25

D

5

E
Q45

The ratio of the number of men to the number of women in a 20-member committe is 3:1. How many women must be added to the 20-member committee so as to make the ratio of men to women 3:2?

A

2

B

5

C

7

D

9

E
Q46

The median of the distribution is

A

25

B

17.5

C

15

D

12.5

E
Q47

The range of the distribution is

A

50

B

30

C

25

D

15

E
Q48

The upper quartile of the distribution is

A

30

B

27.5

C

25

D

17.75

E
Q49

A number is selected at random from the set Y = {18, 19, 20,...,28,29}. Find the probability that the number is prime.

A

1/4

B

3/11

C

1/2

D

3/4

E
Q50

The number of goals scored by a school team in 10 netball matches are as follows: 3, 5, 7, 7, 8, 8, 8, 11, 11, 12. Find the probability that in a match, the school team will score at most 8 goals.

A

7/10

B

2/5

C

3/5

D

1/5

E
Q51

In the diagram, LMT is a straight line. If O is the centre of circle LMN, <OMN = 20°, <LTN = 32° and |NM| = MT, find <LNM.

A

44°

B

46°

C

52°

D

70°

E
Q52

In a bag of oranges, the ratio of the good ones to the bad ones is 5:4. If the number of bad oranges are there altogether?

A

81

B

72

C

54

D

45

E
Q53

What is the probability that two balls are red?

A

5/33

B

5/36

C

103/132

D

31/36

E
Q54

What is the probability that one is green the other is  blue?

A

2/11

B

5/15

C

8/12

D

7/11

E
Q55

If the probability that an event will not occur is q which of the following is true?

A

p -q = 1

B

q - p = 0

C

p + q = 1

D

p + q = 0

E
Q56

What is the range of their ages?

A

14 years

B

20 years

C

30.5 years

D

31 years

E
Q57

What is the mode?

A

22.5 years

B

23.0 years

C

24.0 years

D

24.5 years

E
Q58

How many students are there in the group?

A

25

B

30

C

52

D

55

E
Q59

How many students scored 4 marks and above

A

15

B

11

C

10

D

7

E
Q60

How many students took the test?

A

38

B

22

C

15

D

11

E