CBSE Class 10-Mathematics: Chapter – 14 Statistics Part 15 (For CBSE, ICSE, IAS, NET, NRA 2022)
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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