PG TRB MATHS FREE ONLINE TEST-1

1.If the sum of the squares of the rank difference of 9 pairs is 80 the correlation

coefficient between them is.

2.The odds that the person X speaks the truth are 3:2 and the odds that a person Y

epeaks the truth are 5:3 In what percentage of cases are they likely to contradict each other an identical point

3.A box contains bred, 4 white and 5 black balls, A person draw 4 balls from the box at

random find the probalility that among the balls draw there is atleast one ball in each colour

4.A box contains 5 red and 4 white balls. 2 balls are drawn succeesively from the box

without replacement and it is noticed that second one is white .what is the probability that is also white.

5.f(x) = { Ae5' is a pprobabilits density fuction of a continuous random variable

lo, otherwise X, then the value of A is,

6.If the regression line Coinside then which of the following is false?

7.The variance of first 13 natural numbers is

8. A random variable X assumes only value +1 and -1 each with equal probabilities E(X) is equal to

9.Karl pearson coefficient of skewness is -0.7 and the value of the median and standard derivation are 12.8 and 6 respectively, Find the mean.

10.The first three moments of a distribution about the value 2 variable are 1,16 and -40,

then find My. H'z