The mean of a certain number of observations is x̄. If each observation is multiplied by m (m ≠ 0) and then increased by n, then the mean of new observations is :

1. $\Big(\dfrac{\bar x}{m} + n\Big)$

2. m $\bar x$ + n

3. m $\bar x$ − n

4. $\Big(\dfrac{\bar x}{m} - n\Big)$

The mean of 100 observations is 50. If one of the observations was misread as 50 instead of 40, the correct mean is :

1. 40

2. 49.9

3. 50

4. 50.1

Consider the table given below :

The mean of the marks given above is :

1. 6

2. 18

3. 27

4. 28

If the mean of the following distribution is 27, then the value of p is :

1. 6

2. 7

3. 9

4. 11