
The following table gives the distribution of the lifetime of neon lamps
Lifetime
(in hours)
Number of
lamps
If the median lifetime of a lamp is , find (correct up to two places of decimal).
(in hours)
lamps


Important Questions on Statistics
surnames were randomly picked up from a local telephone directory and the frequency distribution of the number of letters in the English alphabet in the surnames was obtained as follows
Number of letters | ||||||
Number of surnames |
Determine the median number of letters in the surnames. Find the mean number of letters in the surnames? Also, find the modal size of the surnames.

The distribution below gives the weights of students of a class. If the median weight of the students is , find (correct up to two places decimal).
Weight (in ) | |||||||
Number of students |

The following distribution gives the daily income of workers of a factory.
Daily income (in Rupees) | |||||
Number of workers |
Convert the distribution above to a less than type cumulative frequency distribution, and draw its ogive.

During the medical check-up of students of a class, their weights were recorded as follows:
Weight (in kg ) | Number of students |
Less than Less than Less than Less than Less than Less than Less than Less than |
Draw a less than type ogive for the given data. Hence, obtain the median weight from the graph and verify the result by using the formula.

The following table gives production yield per hectare of wheat of farms of a village.
Production yield | ||||||
Number of farmers |
Change the distribution to a more than type distribution and draw its ogive.
