Confidence Statements

what is the margin of error formula?

1/√n \* 100

what is the confidence interval?

p̂ ± M.E

confidence statements are always about?

p as estimated from p̂

why can we use the normal curve for calculating confidence intervals?

because SRS are normal samples that will distribute normally

what is the formula for calculating margin of error for a confidence interval

p̂ ± ^^z \* √ p̂ (1-p̂)/n x 100^^ margin of error

what is the critical z score for 95% (0.05) confidence?

1\.96

what is the critical z score for 99% (0.01) confidence?

2\.58

why does C.I increase when C.L increases?

if you want to be more certain (confident) that p is within the CI, the CL has to increase

why does CI decrease when sample size increases?

because as sample size increases, all p̂s become more accurate (closer to p). the CI shrinks to reflect this

what is the formula for ME of mean?

x̄ ± ^^z \* s/√ n^^ margin of error