Two sets each of `20` observations, have the same standard deviation`5`. The first set has a mean` 17 `and the second set mean` 22` then the standard deviation of the combining the given two sets is

Two sets each of 20 observations have the same standard derivation 5. The first sethas a mean 17 and second a mean 22. Then the standard deviation of the set obtained by combining the given two sets.

The variance of a set of data is 169. Then the standard deviation of the data is :

Find the mean, variance and standard deviation of the number of tails in two tosses of a coin.

If standard deviation of a set of observation is 4 and if each of the observations is divided by 4, then the standard deviation of new set of observations is

The variance of a set of data is 196. Then the standard deviation of the data is.

Calculate the mean and standard deviation of first natural numbers.

For a group containing 100 observations, the arithmetic mean and standard deviation are 8 and sqrt(10.5) . For 50 observations selected from the 100 observations, the arithmetic mean and standard deviations are 10 and 2 respectively. Find the arithmetic mean and the standard deviation of the other half.