Question 890118: Can you please show me how to work this step by step? A magazine company received 12 entries in its latest sweepstakes. the probability of receiving a magazine subscription order with an entry form is 0.4. What is the probability that no more than 5 of the entry forms will include an order?
Answer by Okamiden(22)   (Show Source):
You can put this solution on YOUR website! First, you need to identify what kind of distribution you have. Here, it's a binomial since there's a constant probability and only two outcomes per unique event.
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We thus have a binomial with n=12, p=0.4. In short, we write B(12, 0.4).
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To find the probability that 5 or less entry forms will include an order, we use a binomial table. (We could calculate it by hand, but it involves repeating the same formula 6 times and I'm sure this is not what you're supposed to do in this problem).
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I used this table, you should have your own, though.
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http://mat.iitm.ac.in/home/vetri/public_html/statistics/binomial.pdf
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Just search for n=12. p=0.4 and, for us, we want the probability P(X<=5). That is exactly given by the value in the table at n=12, p=0.4 and x=5.
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The value is 0.6652, or 66.52%.
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Hope that helps.
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