21.  The formula of calculating mean for hyper geometric probability distribution is 
a.  n (m ⁄ n) 
b.  m (n ⁄ n) 
c.  n (n ⁄ m) 
d.  n (m ⁄ n) 
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Answer: (d).n (m ⁄ n)

22.  The formula in which the binomial distribution approaches normal probability distribution with the help of normal variable is written as 
a.  x  qn divided by square root of pq 
b.  x  np divided by square root of npq 
c.  x + np divided by square root of np 
d.  x  pq divided by square root of npq 
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Answer: (b).x  np divided by square root of npq

23.  If the value of m in beta distribution is 35 and the value of n in beta distribution is 50 then the expected value of random variable x in beta distribution is 
a.  0.411 
b.  0.311 
c.  0.511 
d.  0.211 
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Answer: (a).0.411

24.  In a negative binomial distribution of probability, the random variable is also classified as 
a.  discrete random variable 
b.  continuous waiting time random variable 
c.  discrete waiting time random variable 
d.  discrete negative binomial variable 
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Answer: (c).discrete waiting time random variable

25.  The demand of products per day for three days are 21, 19, 22 units and their respective probabilities are 0.29, 0.40, 0.35. The profit per unit is $0.50 then the expected profits for three days are 
a.  21, 19, 22 
b.  21.5, 19.5, 22.5 
c.  0.29, 0.40, 0.35 
d.  3.045, 3.8, 3.85 
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Answer: (d).3.045, 3.8, 3.85
