SOLUTION: in a survey , 65% of Americans said they own an answering machine. If 20 Americans are selected randomly a) find the probabilities that at least 18 people own an answering machine
Algebra.Com
Question 438069: in a survey , 65% of Americans said they own an answering machine. If 20 Americans are selected randomly a) find the probabilities that at least 18 people own an answering machine and b) find the mean and the standard deviation the number of people owning an answering machine .
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
in a survey , 65% of Americans said they own an answering machine.
-----------------------------------------------
If 20 Americans are selected randomly
a) find the probabilities that at least 18 people own an answering machine
P(18<= x <=20) = 1-binomcdf(20,0.65,17) = 0.0121
------------------------------------------------------
b) find the mean and the standard deviation the number of people owning an answering machine .
mean = np = 20*0.65 = 13
std = sqrt(13*0.35) = 2.1331
===============================
cheers,
Stan H.
------------------------------
RELATED QUESTIONS
In a survey, 65% of Americans said they own an answering machine. If 12 Americans are
(answered by robertb)
In a survey 63% of Americans said they own an answering machine. if 14 Americans are... (answered by stanbon)
In a survey, 63% of Americans said they own an answering machine. If 14 americans are... (answered by stanbon)
In a survey, 70% of Americans said they own an answering machine. If 14 Americans are... (answered by Boreal)
In a survey, 40% of Americans said they owned an answering machine. If 10 Americans are... (answered by Boreal)
According to a local survey 80% of Americans own a car. If you randomly select 3... (answered by FrankM)
The percentage of Americans who are vegetarians is 3.2%. Four people are randomly... (answered by stanbon)
The percentage of Americans who are vegetarians is 3.2%. Four people are randomly... (answered by ewatrrr)
If 18% of all Americans are underweight, find the probability two randomly selected... (answered by ikleyn)