The mean of 5 numbers is 18. If one number is excluded, the mean of remaining numbers becomes 16. Find the excluded number.

If the mean of observations x, x + 2, x + 4, x + 6 and x + 8 is 11, find the value of x.

12 observations in a data are written in descending order. If the first observation is doubled, the median will :

1. remain same

2. increase by 12

3. decrease by 12

4. change by 12

Median of numbers 10, 12, 9, 8, 10, 12, 10, 6 and 4 is :

1. 12

2. 10

3. 6

4. 9