The mean deviation for n observations x₁, x₂, ….., x_n from their mean is given by

Let x₁, x₂, ……x_n, be n observations. Let y_i = ax_i + b for I = 1, 2, ….., n, where a and b are constant. If the mean of is 48 and their standard deviation is 12, the mean of is 55 and standard deviation of is 15, the values of a and b are

The mean deviation of the data 3, 10, 10, 4, 7, 10, 5 from the mean is

Let x₁, x₂, ….., x_n be n observations and be their arithmetic mean. The standard deviation is given by

The standard deviation of the observations 6, 5, 9, 13, 12, 8, 10 is