If the mean of the data x₁, x₂, x₃, ….., x_n is 'a', then the mean of the data x₁ + a, x₂ + a, …., x_n + a is :

1. a

2. 2a

3. $\dfrac{1}{2}$a

4. $\dfrac{a}{3}$

If the mean of the data y₁, y₂, y₃, …., y_n is 102, then the mean of the data 5y₁, 5y₂, 5y₃, …., 5y_n is :

1. 102

2. 204

3. 510

4. 606

The mean of 25 observations was calculated to be 44. Later on it was found that two of the observations 34 and 46 were wrongly copied as 28 and 42. The correct mean will be :

1. 39.4

2. 40.4

3. 44.4

4. 43.9

The median of the following observations : 11, 12, 14, 18, (x + 4), 30, 32, 35, 41 arranged in ascending order is 24. The value of x is :

1. 19

2. 20

3. 21

4. 21.5