EXERCISE 28 B

1.Fill in the blanks:

(i) The difference between the maximum and the minimum observations in a data is called the ___ of the data.

(ii) The number of observations in a particular class interval is called the ___ of the class interval.

2.Find:

(i) Lower limit of the class interval 46 – 53

(ii) Upper limit of the class interval 30 — 35

(iii) The range of the data 2 , 9 , 17 , 25 , 4 , 11

3.Find the class marks of the following table:

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<table style=”border-collapse: collapse;” border=”1″>

<tr><th>Weights in kg</th><td>10-20</td><td>20-30</td><td>40-50</td><td>50-60</td></tr>

<tr><th>Class-marks</th><td>-</td><td>-</td><td>-</td><td>-</td><td>-</td></tr>

</table>

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4.The following are the monthly rents (in rupees) of 30 shops

42,49,37,82,37,75,62,54,79,84,75,63,44,74,36,69,54,48,74,39,48,45,61,71,47,38,80,51,31,47.Using the class intervals of equal width in which one class interval being 40-50 (excluding 50) . Construct a frequency table for the above data .

5.On the first day of school , a school bus brought 40 students to a high school . Their vages were as follows:

13,11,9,10,15,6,5,8,15,16,17,7,8,10,13,17,14,12,14,13,6,11,9,10,12,17,16,7,8,9,6,10,6,8,13,9,6,8,12

Group the ages into four equal classes with class intervals 4-8 etc and construct a frequency table

6.Find the mean of each of the following frequency distributions.

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<tr><th>Class</th><td>0-10</td><td>10-20</td><td>30-40</td><td>40-50</td><td>50-60</td><td>60-70</td></tr>

<tr><th>Frequency</th><td>4</td><td>4</td><td>7</td><td>10</td><td>12</td><td>8</td><td>5</td></tr>

</table>

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