Question

If n=18, ¯x(x-bar)=47, and s=4, find the margin of error at a 80% confidence level

Give your answer to two decimal places.

Answer 1

Solution :

Given that,

= 47

s =4

n =18 Degrees of freedom = df = n - 1 =18- 1 =17

At 80% confidence level the t is ,

= 1 - 80% = 1 - 0.80 = 0.20

  / 2= 0.20 / 2 = 0.10

t /2,df = t0.10, 17 = 1.333 ( using student t table)

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

= 1.333* ( 4/ 18)

E=1.26

answered by: anonymous