For the following questions answer them individually
If the arithmetic mean of the series $$a_1, a_2, ... a_n$$ is A and the arithmetic mean of the series $$b_1, b_2, ... b_n$$ is B, then the arithmetic mean of the series
$$a_1 + b_1, a_2 + b_2, ..., a_n + b_n$$ is
If $$\sigma$$ is the standard deviation of $$x_1, x_2, x_3, ......, x_n$$ then the standard deviation of observations $$5x_1 - 11, 5x_2 - 11, 5x_3 - 11, ....., 5x_n - 11$$ is
In a data with 12 observations, the coefficient of rank correlation is zero, then
$$\sum_{i=0}^{12}d_{i}^{2} =$$
If a number is selected at random from the first 120 natural numbers, then the probability that it is a multiple of 6 or 8 is
When 5 boys and 6 girls sit in a row at random, the probability that no two boys sit together is
When two persons are selected at random from 15 persons who sat around a table, the probability that the selected persons are not adjacent to each other is
Out of the four digit numbers with distinct digits fonned by using the digits 1, 2, 3, 4, 5. A number is chosen at random. Then the probability that the chosen number is odd is