Statistics Questions (255)

The mean of $40$ observations is $20$ and their standard deviation is $5$. If the sum of the squares of the observations is $k$, then the value of $\frac{k}{160}$ is

The mean and standard deviation of marks of 200 students were 40 and 15 respectively. Later it was discovered that a score of 40 was wrongly read as 50. The correct standard deviation is

The mean and variance of 7 observations are 8 and 16 respectively. If 5 of the observations are 2, 4, 10, 12, 14, then the remaining two observations are

For a data set of 10 observations with mean $\bar{x} = 50$, $\displaystyle\sum(x_i-\bar{x})^2 = 250$. The coefficient of variation (CV) is

Let \(\bar{X}\) and MD be the mean and the mean deviation about \(\bar{X}\) of \(n\) observations \(x_i,\ i = 1, 2, \ldots, n\). If each of the observations is increased by 5, then the new mean and the mean deviation about the new mean, respectively, are