Question

If n=26, ¯xx¯ (x-bar)=50, and s=6, find the margin of error at a 99% confidence level (use at least three decimal places)

Answer 1

)solution

Given that,

= 50

s =6

n = 26

Degrees of freedom = df = n - 1 = 26 - 1 = 25

At 99% confidence level the t is ,

= 1 - 99% = 1 - 0.99 = 0.01

/ 2 = 0.01 / 2 = 0.005

t /2  df = t0.005,25 = 2.787    ( using student t table)

Margin of error = E = t/2,df * (s /n)

= 2.787 * ( 6/ 26) = 3.279