# PPSC Past Papers of Commerce

(i) Four coins are tossed simultaneously, in how many distinct ways these coin can show up?
(a) 8 (b) 4  (c) 16  (d) 32  (e) None of these
(ii)  In how many ways five people can fill five distinct posts?
(a) 60  (b) 120  (c) 25  (d) 50  (e) None of these
(iii)  Let X be a random variable distributed like Binomial with n=10 and p=0.345, then what will be E(X)?
(a) 34.5  (b) 3.45  (c) 0.0345  (d) None of these
(iv)  What is P(AB) equals to, when A and B are mutually exclusive events?
(a) P(A)+P(B) (b) P(A) x P(B)  (c) P(A)+P(B)-P(AB) (d) None of these
(v)  What is P(AB) equals to when A and B are two independent events?
(a) P(A)+P(B) (b) P(A) x P(B)  (c) P(A)+P(B)-P(AB) (d) None of these
(vi)  For which probability distribution function mean and variance are equal?
(a) Normal (b) Binomial (c) Poisson  (d) Gamma  (e) None of these
(vii)  How many ways all possible distinct committees of 3 students can be formed from a class of 10
students?
(a) 30  (b) 120  (c) 125  (d) 720  (e) None of these
(viii) Let Y be a random variable distributed like Binomial with n=5 and p=0.70, then what will be the
variance of Y?(a) 0.105  (b) (0.105)2(c) 3.5  (d) 0.14  (e) None of these
(ix)  Let Y= α + β X + error. What β is called?
(a) mean of X (b) Y-intercept (c) slope  (d) variance of Y (e) None of these
(x)  If the standard deviation of a random variable X is 5, then what will be the standard deviation of Y=4x+2?
(a) 400  (b) 20  (c) 22  (d) 402  (e) None of these
(xi)  A question was asked, whose answer is either YES or NO, to 150 individuals from a section of
population, of them 90 gave YES answer. What will be the value of Chi-square if the hypothesis
to be tested is P(YES)=P(NO)?
(a) 5  (b) 6  (c) 15  (d) 25  (e) None of these
(xii)  What does the probability of “rejecting null hypothesis when it is true’’ called?
(a) Type-I error (b) Type-II error (c) Level of confidence
(d) Least error (e) None of these