Question 806676: Edinburgh City Council is conducting a survey of people who live in the Morningside area of the city. The Council is seeking to find out the amount of money that each household spends on electricity bills every month, and offering money-saving tips to residents.
i. An interviewer will be sent out to fourteen private houses on weekday evenings over the course of
one week. The City Council has previous experience in this area and believes that there is a 75% chance of finding someone at home in the evening.
a. Whatistheprobabilitythatthereissomeoneathomein11houses?
b. Whatistheprobabilitythattherewillbesomeoneathomein5houses?
c. Whatistheprobabilitythattherewillbesomeoneathomein11ormorehouses?
Answer by edjones(8007)   (Show Source):
You can put this solution on YOUR website! a)
n=14, x=11, p=.75 q=.25
14C11=364
364*p^11*q^3
=.240
.
b)
n=14, x=11, p=.75 q=.25
14C5=2002
2002*p^5*q^9
=.00181
.
c)
From a calculator at:
http://vassarstats.net/textbook/ch5apx.html
x=11 .2402
x=12 .1802
x=13 .0832
x=14 .0178
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====>.5213
.
Ed
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