The mean of 20 observations is 15. On checking it was found that two observations were wrongly copied as 3 and 6. If wrong observations are replaced by correct values 8 and 4, then the correct mean is

When  x_i and y_i are two variables (i=1,2,...,n) with geometric means  G₁ and G₂ respectively then the geometric mean of  x_i/ y_i is

The algebraic sum of the deviations of a set of n values from their arithmetic mean is

A distribution with more than two modes is called

10 is the mean of a set of 7 observations and 5 is the mean of a set of 3 observations. The mean of a combined set is given by

The mean and median of 100 items are 50 and 52 respectively. The value of the largest item is 100. It was later found that it is actually 110. Therefore, the true mean is ___ and the true median is _____