railway RRB Technician Grade 1 Mock Test 2024 Mathematics Statistics Variance and Standard Deviation
The mean and the standard deviation of 19 observations are given to be 6 and 2 respectively. If every observation is multiplied by 3, the mean and the variance of the new series will be respectively.
1
18 and 2√3
2
2 and 4
3
18 and 36
4
6 and 12