test 4 9.1
Margin of Error given upper bound and lower bound
E= (U-L)/2
What is the general relationship, if any, between the sample size and the margin of error?
Increasing the sample size by a factor M results in the margin of error decreasing by a factor of StartFraction 1 Over StartRoot Upper M EndRoot EndFraction .
point estimate for the population proportion
P^ = x/n
point estimate
the value of a statistic that estimates the value of a parameter
By how many times does the sample size have to be increased to decrease the margin of error by a factor of one half
The sample size must be increased by a factor of 4 to decrease the margin of error by a factor of one half .
sample size needed when prior estimate is unavailable
n=.25(Z(subalpa)/2 /E)^2
sample size needed given a prior estimate
n=p^(1-p^) (Z(subalpha/2)/(E) ^2)
point estimate given upper bound and lower bound
p^= (U+L)/2