Students can Download Maths Chapter 13 Statistics Ex 13.3 Questions and Answers, Notes Pdf, KSEEB Solutions for Class 8 Maths helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations.

## Karnataka Board Class 8 Maths Chapter 13 Statistics Ex 13.3

Question 1.

Runs scored by 10 batsmen in a one-day cricket match are given. Find the average run scored. 23, 54, 08, 94, 60, 18, 29, 44, 05, 86

Answer:

Σ x = 23 + 54 + 08 + 94 + 60 + 18 + 29 + 44 + 05 + 86 = 421

N = 10

Average = Mean =

Question 2.

Find the mean weight form the following table:

Weight (kg) | 29 | 30 | 31 | 32 | 33 |

No. of children | 02 | 01 | 04 | 03 | 05 |

Answer:

Weigh t(kg) | No. of children(x) | ‘ f |

29 | 02 | 58 |

30 | 01 | 30 |

31 | 04. | 124 |

32 | 03 | 96 |

33 | 05 | 164 |

N= 15 | Zf = 473 |

Mean = \(\frac{\Sigma f_{X}}{N}=\frac{473}{15}=31.53\)

Question 3.

Calculate the mean for the following frequency distribution.

Mark | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |

Frequency | 3 | 7 | 10 | 6 | 8 | 2 | 4 |

Answer:

Marks | Frequency | Midpoint | fx |

10-20 | 3 | 15 | 45 |

20-30 | 7 | 25 | 175 |

30-40 | 10 | 35 | 350 |

40-50 | 6 | 45 | 270 |

50-60 | 8 | 55 | 440 |

60-70 | 2 | 65 | 130 |

70-80 | 4 | 75 | 300 |

N = 40 | Efx = 1710 |

Mean = \(\frac{\Sigma f_{x}}{N}=\frac{1710}{40}=42.75\)

Question 4.

Calculate the mean for the following frequency distribution.

Mark | 15-19 | 20-24 | 25-29 | 30-34 | 35-39 | 40-44 |

Frequency | 6 | 5 | 9 | 12 | 6 | 2 |

Answer:

Marks. | Frequency | Midpoint | f(X) |

15-19 | 6 | 17 | 102 |

20-24 | 5 | 22 | *110 |

25-29 | 9 | 27 | 243 |

30-34 | 12 | 32 | 384 |

35-39 | 6 | 37 | 222 |

40-44 | 2 | 42 | 84 |

N = 40 | Efx = 1145 |

Mean = \(\overline{X}=\frac{\Sigma f_{X}}{N}=\frac{1145}{40}=28.625\)

Question 5.

Find the median of the data 15,22, 9,20, 6,18,11,25,14.

Answer:

6, 9, 11, 14,(15), 18, 20, 22,25 (Ascending order)

N = 9,

Median = 15.

Question 6.

Find the median of the data 22,28,34, 49, 44, 57,18,10,33, 41, 66, 59.

Answer:

10, 18, 22, 28, 33, 34, 41, 44, 49, 57, 59, 66 (Ascending order)

N = 10

∴ Median =

Question 7.

Find the median for the following frequency distribution table.

Class interval | 110-119 | 120-129 | 130-139 | 140-149 | 150-159 | 160-169 |

Frequency | 6 | 8 | 15 | 10 | 6 | 5 |

Answer:

Class interval | Frequency (f) | Cumulative frequency (fc) |

110-119 | 6 | 6 |

120-129 | 8 | 14 |

130-139 | 15 | 29 |

140-149 | 10 | 45 |

160-169 | 5 | 50 |

N = 50 |

N = 50

\(\frac{\mathrm{N}}{2}=\frac{50^{25}}{\not 2}=25\)

∴ Median class is 130 – 139

LRL = 129.5

Fc = 14

Fm = 15

i = 10

Question 8.

Find the median for the following frequency distribution table.

Class interval | 0-5 | 5-10 | 10-15 | 15-20 | 20-25 | 25-30 |

Frequency | 5 | 3 | 9 | 10 | 8 | 5 |

Answer:

Class interval | Frequency (t) | Cumulative frequency (fc) |

0-5 | 5 | 5 |

5-10 | 3 | 8 |

10-15 | 9 , | 17 |

15-20 | 10 | 27 |

20-25 | 8 | 35 |

25-30 | 5 | 40 |

N = 40 |

N = 40

\(\frac{N}{2}=\frac{40}{2}=20\)

∴ Median class is 15 – 20

LRL = 15

Fc = 17

Fm = 9

i = 5

Question 9.

Find the mode for the following data.

(i) 4,3,1,5,3, 7, 9,6 Answer: Mode = 3

(ii) 22,36,18,22,20,34,22, 42, 46,42

Answer:

Mode = 22

Question 10.

Find the mode for the following data

X | 5 | 10 | 12 | 15 | 20 | 30 | 40 |

f | 4 | 8 | 11 | 13 | 16 | 12 | 9 |

Answer:

Mode = 20 (It has the highest frequency)