CBSE Class 10-Mathematics: Chapter –14 Statistics Part 15
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Question 11:
Following table shows the daily pocket allowances given to the children of a multi-story building. The mean of the pocket allowances is . Find out the missing frequency.
Class Interval | |||||||
Frequency |
Answer:
Let the missing frequency , we have
Class interval | Mid-value | |||
11-13 | 3 | 12 | -3 | -9 |
13-15 | 6 | 14 | -2 | -12 |
15-17 | 9 | 16 | -1 | -9 |
17-19 | 13 | 18 | 0 | 0 |
19-21 | f | 20 | 1 | F |
21-32 | 5 | 22 | 2 | 10 |
23-25 | 4 | 24 | 3 | 12 |
Let assumed mean , Here
We know that mean
Hence, missing frequency
Question 12:
A survey regarding the heights (in cm) of girls of Class of a school was conducted and the following data was obtained. Find the median height.
Height (in cm) | No. of girls |
Less than 140 | |
Less than 145 | |
Less than 150 | |
Less than 155 | |
Less than 160 | |
Less than 165 |
Answer:
We have,
Class Intervals | Frequency (f) | C.F |
Below | ||
Here, which is in the class
Here,
Median height of the girls