Question 1186996: Q.3 An increasing number of consumers believe they have to look out for themselves in the marketplace. According to a
survey conducted by the Yankelovich Partners for USA Weekend magazine, 60% of all consumers have called an 800
or 900 telephone numbers for information about some product. Suppose a random sample of 20 consumers is
contacted and interviewed about their buying habits. [Answers: a) 41.50%, b) 0.3%, c) 0%]
Required:
a) What is the probability that 13 or more of these consumers have called an 800 or 900 telephone numbers for
information about some product?
b) What is the probability that more than 17 of these consumers have called an 800 or 900 telephone numbers
for information about some product?
c) What is the probability that fewer than 5 of these consumers have called an 800 or 900 telephone numbers
for information about some product?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! want binomial n=12 p=0.6
Very straight forward with c. You can look at the table with n=20 p=0.6 and 4. The probability both pdf and cdf is 0.
For b, More than 17 is 18-20. For 18 it is 0.003, and 19 and 20 don't increase that significantly.
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for 13: the calculator will show that for 14 or more (1-biniomcdf(20,0.6,13)=0.2500
Can check that for 13: 0.1659.
for 14: 0.1244
for 15: 0.0746
for 16: 0.0350
for 17: 0.0123
and the rest is 0.003 from above
That is 0.416 or 41.6%
also 1-binomcdf(20,0.6,12), since want 12 but not 13 to get rid of the left side.
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