20% of memory chips made in a certain plant are defective.

[TomJerry]

Problem : 20% of memory chips made in a certain plant are defective.Find the probability that in a lot of 100 randomly chosen for inspection
i) atmost 15 are defective
ii) excatly 15 are defective.
Obtain these probability using normal approximation of binomial probabilities.
Solution

Here mean = np = 100 * 0.2 = 20
S.D. = 4

there P(Z >= 15-20/4) = 0.5 - 0.3944 = 0.1056 [IS THIS CORRECT][/color]

ii) ?

 

[Dickfore]

no. ;)