It costs you $10 to draw a sample size n=1 and measure the attribute of interest. you have a budget of $1,200

a.       Do you have sufficient funds to estimate the population mean for the attribute of interest with a 95% confidence interval 4 units width? Assume that sd= 12

n= {[(Zalpha/2)^2]*[sd]^2}/ se^2

n= (1.96)^2*(12)^2/ (2)^2

n= 138.297 rounded up to 139

There is not enough funds for this one since you’ll need 139 pieces and it costs 10 a piece, you’ll need 1390.

b.      90% confidence interval

n= {[(Zalpha/2)^2]*[sd]^2}/ se^2

n= (1.645)^2*(12)^2/ (2)^2

n=98

There is enough funds since 98 pieces for 10 a piece is equal to 980.