1What sample size would be needed to estimate the true propo

1.What sample size would be needed to estimate the true proportion of students at DU who are wearing backpacks, with 95 % confidence and an error of

Solution

to find the bound on sample size, assuming proportion of students at DU who are wearing backpacks = 0.50

proportion,p = 0.5
error,E = 0.08
alpha,a = 1-0.95 = 0.05
.
Za/2 = Z0.025 = 1.96

sample size,n >= [Za/2 / E]^2 * p(1-p)
n >= [1.96 / 0.08]^2 * 0.5(1-0.5)
n >= 150.06
n = 151