For the following questions answer them individually
If the arithmetic mean of a, b, 7 is 13, then the arithmetic mean of $$a + 3, b - 5$$ and 6 is
If $$ \sigma$$ is the standard deviation of the observatins $$x_{1}, x_{2}, ... , X_{n}$$, then the standard deviation of $$12x_{1} + 13, 12x_{2} + 13, ..... 12x_{n} + 13$$ is
A computer, while calculating the correlation coefficient between two variables X and Y, obtained the following results:
$$N = 25, \sum_{}^{}x= 125, \sum_{}^{}y= 100, \sum_{}^{}x^{2}= 650, \sum_{}^{}y^{2}= 460$$ and $$\sum_{}^{}xy= 508$$
At the time of checking, it is found that it copied two pairs of observations as
in the place of correct pairs
.The correct value of the coefficient of con-elation r is
A and B are two events such that $$P(A) = \frac{2}{3}, P(\overline{A}\cap B) = \frac{1}{6}$$ and $$P(A\cap B) = \frac{1}{3}$$, ther $$P(\overline{A}\cup B) = $$
If $$P(A) = 0.7, P(\overline{B}) = 0.45$$ and $$P(\overline{A} \cup \overline{B}) = 0.6$$, then $$P(A \cup B) =$$
A box has 5 white and 2 red balls. Another box has 3 white and 4 red balls. One ball is randomly seleckd from the first box and it is transferred to second box. Then one ball is randomly drawn from the second box. The probability that it is red is