Question

The Magazine Mass Marketing Company has received 18 entries in its latest sweepstakes. They know that the probability of receiving a magazine subscription order with an entry form is 0.5. What is the probability that no more than 5 of the entry forms will include an order? Round your answer to four decimal places.

Answer 1

Let X: Number of magazine subscription orders received with an entry form.

Now X ~ Binomial (18 , 0.5)

P(X=x) =

X	P(X=x)
0	0.00000381
1	0.00006866
2	0.00058365
3	0.00311279
4	0.01167297
5	0.03268433
6	0.07081604
7	0.12139893
8	0.16692352
9	0.18547058
10	0.16692352
11	0.12139893
12	0.07081604
13	0.03268433
14	0.01167297
15	0.00311279
16	0.00058365
17	0.00006866
18	0.00000381

We have to find the probability :

P(no more than 5 of the entry forms will include an order)

= P(X<=5)

= P(X=0) + P(X=1) + P(X=2) + P(X=3) + P(X=4) + P(X=5)

= 0.048126220703125