Questions & Answers: "Statistics and Probability"

Complete guide to "Statistics and Probability" for Math students. Below you will find important questions and model answers to help you prepare.

33 Questions

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Question 1

1 Mark

The marks obtained by 17 students in a mathematics test (out of 100) are given below: 91, 82, 100, 100, 96, 65, 82, 76, 79, 90, 46, 64, 72, 68, 66, 48, 49. The range of the data is:

Options

Option A

46

Option B is correct

54

Option C

90

Option D

100

Question 2

1 Mark

The class-mark of the class 130-150 is:

Options

Option A

130

Option B

135

Option C is correct

140

Option D

145

Question 3

1 Mark

A die is thrown 1000 times, and the outcomes were recorded as follows. Now if the die is thrown once more, then the probability that it shows 5 is:

Diagram for Question 3

Options

Option A

9/50

Option B is correct

3/20

Option C

4/25

Option D

7/25

Question 4

1 Mark

The class mark of the class 90-120 is

Options

Option A

90

Option B is correct

105

Option C

115

Option D

120

Question 5

1 Mark

The range of the data: 25, 18, 20, 22, 16, 6, 17, 15, 12, 30, 32, 10, 19, 8, 11, 20

Options

Option A

10

Option B

15

Option C

18

Option D is correct

26

Question 6

1 Mark

In a frequency distribution, the mid value of a class is 10 and the width of the class is 6. The lower limit of the class is:

Options

Option A

6

Option B is correct

7

Option C

8

Option D

12

Question 7

1 Mark

The width of each of five continuous classes in a frequency distribution is 5 and the lower class-limit of the lowest class is 10. The upper class-limit of the highest class is:

Options

Option A

15

Option B

25

Option C is correct

35

Option D

40

Question 8

1 Mark

Let m be the mid-point and l be the upper-class limit of a class in a continuous frequency distribution. The lower-class limit of the class is:

Options

Option A

2m + l

Option B is correct

2m – l

Option C

m – l

Option D

m – 2l

Question 9

1 Mark

The class marks of a frequency distribution are given as follows: 15, 20, 25, ... The class corresponding to the class mark 20 is:

Options

Option A

12.5 – 17.5

Option B is correct

17.5 – 22.5

Option C

18.5 – 21.5

Option D

19.5 – 20.5

Question 10

1 Mark

In the class intervals 10-20, 20-30, the number 20 is included in:

Options

Option A

10-20

Option B is correct

20-30

Option C

both the intervals

Option D

none of these intervals

Question 11

1 Mark

A grouped frequency table with class intervals of equal sizes using 250-270 (270 not included in this interval) as one of the class interval is constructed for the following data: 268, 220, 368, 258, 242, 310, 272, 342, 310, 290, 300, 320, 319, 304, 402, 318, 406, 292, 354, 278, 210, 240, 330, 316, 406, 215, 258, 236. The frequency of the class 310-330 is:

Options

Option A

4

Option B

5

Option C is correct

6

Option D

7

Question 12

1 Mark

A grouped frequency distribution table with classes of equal sizes using 63-72 (72 included) as one of the class is constructed for the following data: 30, 32, 45, 54, 74, 78, 108, 112, 66, 76, 88, 40, 14, 20, 15, 35, 44, 66, 75, 84, 95, 96, 102, 110, 88, 74, 112, 14, 34, 44. The number of classes in the distribution will be:

Options

Option A

9

Option B is correct

10

Option C

11

Option D

12

Question 13

1 Mark

To draw a histogram to represent the following frequency distribution, the adjusted frequency for the class 25-45 is:

Diagram for Question 13

Options

Option A

6

Option B

5

Option C

3

Option D is correct

2

Question 14

1 Mark

The mean of five numbers is 30. If one number is excluded, their mean becomes 28. The excluded number is:

Options

Option A

28

Option B

30

Option C

35

Option D is correct

38

Question 15

1 Mark

If the mean of the observations: x, x + 3, x + 5, x + 7, x + 10 is 9, the mean of the last three observations is

Options

Option A Diagram for Option A
Option B Diagram for Option B
Option C is correctDiagram for Option C
Option D Diagram for Option D

Question 16

1 Mark

If

Diagram for Question 16

Options

Option A

-1

Option B is correct

0

Option C

1

Option D

n - 1

Question 17

1 Mark

If each observation of the data is increased by 5, then their mean

Options

Option A

remains the same

Option B

becomes 5 times the original mean

Option C

is decreased by 5

Option D is correct

is increased by 5

Question 18

1 Mark

Let

Diagram for Question 18

Options

Option A Diagram for Option A
Option B is correctDiagram for Option B
Option C Diagram for Option C
Option D Diagram for Option D

Question 19

1 Mark

If

Diagram for Question 19

Options

Option A Diagram for Option A
Option B is correctDiagram for Option B
Option C Diagram for Option C
Option D Diagram for Option D

Question 20

1 Mark

If

Diagram for Question 20

Options

Option A Diagram for Option A
Option B Diagram for Option B
Option C is correctDiagram for Option C
Option D Diagram for Option D

Question 21

1 Mark

The mean of 100 observations is 50. If one of the observations which was 50 is replaced by 150, the resulting mean will be:

Options

Option A

50.5

Option B is correct

51

Option C

51.5

Option D

52

Question 22

1 Mark

There are 50 numbers. Each number is subtracted from 53 and the mean of the numbers so obtained is found to be –3.5. The mean of the given numbers is:

Options

Option A

46.5

Option B

49.5

Option C

53.5

Option D is correct

56.5

Question 23

1 Mark

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 13th observations is 40, the 13th observation is:

Options

Option A

23

Option B is correct

36

Option C

38

Option D

40

Question 24

1 Mark

The median of the data 78, 56, 22, 34, 45, 54, 39, 68, 54, 84 is

Options

Option A

45

Option B

49.5

Option C is correct

54

Option D

56

Question 25

1 Mark

For drawing a frequency polygon of a continuous frequency distribution, we plot the points whose ordinates are the frequencies of the respective classes and abscissae are respectively:

Options

Option A

upper limits of the classes

Option B

lower limits of the classes

Option C is correct

class marks of the classes

Option D

upper limits of preceding classes

Question 26

1 Mark

Median of the following numbers 4, 4, 5, 7, 6, 7, 7, 12, 3 is

Options

Option A

4

Option B

5

Option C is correct

6

Option D

7

Question 27

1 Mark

Mode of the data 15, 14, 19, 20, 14, 15, 16, 14, 15, 18, 14, 19, 15, 17, 15 is

Options

Option A

14

Option B is correct

15

Option C

16

Option D

17

Question 28

1 Mark

In a sample study of 642 people, it was found that 514 people have a high school certificate. If a person is selected at random, the probability that the person has a high school certificate is:

Options

Option A

0.5

Option B

0.6

Option C

0.7

Option D is correct

0.8

Question 29

1 Mark

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:

Options

Option A

0.25

Option B

0.50

Option C is correct

0.75

Option D

0.80

Question 30

1 Mark

In a medical examination of students of a class, the following blood groups are recorded. And a student is selected at random from the class. The probability that he/she has blood group B, is:

Diagram for Question 30

Options

Option A

1/4

Option B

13/40

Option C is correct

3/10

Option D

1/8

Question 31

1 Mark

Two coins are tossed 1000 times, and the outcomes are recorded as below. Based on this information, the probability for at most one head is:

Diagram for Question 31

Options

Option A

1/5

Option B

1/4

Option C is correct

4/5

Option D

3/4

Question 32

1 Mark

80 bulbs are selected at random from a lot and their lifetime (in hours) is recorded in the form of a frequency table given below. One bulb is selected at random from the lot. The probability that its life is 1150 hours, is

Diagram for Question 32

Options

Option A

1/80

Option B

7/16

Option C is correct

0

Option D

1

Question 33

1 Mark

80 bulbs are selected at random from a lot and their lifetime (in hours) is recorded in the form of a frequency table given below. The probability that bulbs selected randomly from the lot has life less than 900 hours is:

Options

Option A

11/40

Option B

5/16

Option C

7/16

Option D is correct

9/16