SOLUTION: If 90% of all people between the ages of 30 and 50 drive a car, find the probability for a sample of 20 people in that age group that at most 15 drive a car.
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-> SOLUTION: If 90% of all people between the ages of 30 and 50 drive a car, find the probability for a sample of 20 people in that age group that at most 15 drive a car.
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Question 1171781: If 90% of all people between the ages of 30 and 50 drive a car, find the probability for a sample of 20 people in that age group that at most 15 drive a car.
I will use the Excel standard function BINOM.DIST to facilitate calculations.
It has the analogue --- the standard function binompdf in pocket calculators TI-83 and TI-84.
Probability that at most 15 of 20 do drive a car is
P = P(0) + P(1) + P(2) + . . . + P(15) = = BINOM.DIST(15, 20, 0.9, TRUE) = 0.0432 = 4.32%. ANSWER
The Excel standard function BINOM.DIST allows calculating this sum in one click.
Solved.
On Excel function BINOM.DIST, see its description everywhere, for example
https://support.office.com/en-us/article/binom-dist-function-c5ae37b6-f39c-4be2-94c2-509a1480770c
On binompdf function for pocket calculators TI-83 and TI-84 see the link
http://users.rowan.edu/~schultzl/ti/binomial.pdf
