Question

if n=27, x bar =39, s=3, find the margin of error at a 98% confidence interval.

Answer 1

Solution :

Given that,

= 39

s =3

n =27 Degrees of freedom = df = n - 1 =27 - 1 =26

At 98% confidence level the t is

= 1 - 98% = 1 - 0.98 = 0.02

/ 2 = 0.02/ 2 = 0.01

t /2,df = t0.01,26 =2.479 ( using student t table)

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

=2.479 * ( 3/ 27)

= 1.4313

Margin of error = E =1.4313