SOLUTION: A mail-order company has an 8% success rate. If it mails advertisements to 600 people, find the probability of getting fewer than 40 sales.

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Question 1150407: A mail-order company has an 8% success rate. If it mails advertisements to 600 people, find the probability of getting fewer than 40 sales.
Answer by VFBundy(438) About Me  (Show Source):
You can put this solution on YOUR website!
n = 600
p = 0.08
q = 0.92

M = np = 600(0.08) = 48

SD = sqrt%28n%2Ap%2Aq%29 = sqrt%28600%280.08%29%280.92%29%29 = sqrt%2844.16%29 = 6.645

P(x < 40) ----> P(x < 39.5)

z = %2839.5+-+M%29%2FSD = %2839.5+-+48%29%2F6.645%29 = %28-8.5%29%2F6.645 = -1.28

Look up -1.28 on a z-table. The result is 0.1003. This means there is a 0.1003 probability of fewer than 40 sales.