Find the Probability Distribution for the number of Jazz Records, when 4 Records are selected at random from collection consisting of 5 Jazz Records, 2 Classical Records and 3 Polka Records. Find the expected number.
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x P(x)
0 5c4/10c4 ....... = 5/210
1 5c1*5c3/10c4 = 50/210
2 5c2*5c2/10c4 = 100/210
3 5c3*5c1/10c4 = 50/210
4 5c4/10c4 ....... = 5/210
E[x] = (5/10)*4 = 2 (short way),
or (0*5+1*50+2*100+3*50+4*5)/210 = 2 (long way)
0 5c4/10c4 ....... = 5/210
1 5c1*5c3/10c4 = 50/210
2 5c2*5c2/10c4 = 100/210
3 5c3*5c1/10c4 = 50/210
4 5c4/10c4 ....... = 5/210
E[x] = (5/10)*4 = 2 (short way),
or (0*5+1*50+2*100+3*50+4*5)/210 = 2 (long way)
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If 4 are selected from 5 Jazz, all will be Jazz. What is your question? P. D. of classical records or P. D. of Polka?