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#### Page No 98:

#### Question 1:

Now look at this problem: the heights of 40 people, in centimeters, are given below. Make a frequency table of this data.

175 |
143 |
177 |
163 |
170 |
168 |
156 |
168 |
145 |
160 |
||||||||||

159 |
154 |
148 |
166 |
168 |
150 |
164 |
160 |
176 |
163 |
||||||||||

140 |
170 |
165 |
168 |
169 |
174 |
158 |
148 |
155 |
165 |
||||||||||

162 |
167 |
171 |
165 |
171 |
167 |
159 |
171 |
167 |
180 |

#### Answer:

The given ungrouped data consists of heights of 40 people ranging from 140 cm to 180 cm.

The frequency table of the given data can be shown as follows:

Height (cm) |
Number of People |
||

140−150 |
5 |
||

150−160 |
7 |
||

160−170 |
18 |
||

170−180 |
9 |
||

180−190 |
1 |

#### Page No 99:

#### Question 1:

Look at this table. It classifies the days of the months of June, July and August according to the rainfall received in a locality.

Rain (mm) |
Days |
||

10 − 20 |
8 |
||

20 − 30 |
10 |
||

30 − 40 |
14 |
||

40 − 50 |
20 |
||

50 − 60 |
15 |
||

60 − 70 |
8 |
||

70 − 80 |
7 |
||

80 − 90 |
6 |
||

90 − 100 |
4 |

Draw a histogram for this data.

#### Answer:

The classes in the given table can be arranged in a histogram plot as follows:

#### Page No 104:

#### Question 1:

The sizes of shirts sold in a shop are as follows:

36, 38, 30, 40, 34, 42, 30, 46, 40, 38, 34, 40, 38, 40, 42, 30, 40, 38, 44, 40, 32, 40, 32, 44, 38

Compute the mean, median and mode. Among these, which is the most important one for the seller? Discuss.

#### Answer:

Mean of the given data =

=

= 37.84

By arranging the given data in ascending order, we have:

30, 30, 30, 32, 32, 34, 34, 36, 38, 38, 38, 38, 38, 40, 40, 40, 40, 40, 40, 40, 42, 42, 44, 44, 46

Median of a data is the middle observation of the data.

∴ Median of the given data = 13^{th} observation = 38

The observation which is repeated most is the mode of the data.

In the given data, the observation 40 is repeated 7 times.

∴ Mode of the given data = 40

As the sale of a seller depends on the demand of the product therefore, the size of the shirt which is mostly sold is most important for the seller as his sale for that particular size of shirt is more than the other sizes.

Thus, mode is most important for the seller.

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