Question

Express the confidence interval ( 66.1 , 301.5 ) in the form of ¯ x ± M E . ¯ x ± M E =______ ± ______.

Can you please tell me how to calculate this on my TI-83 plus calculator? Thank you!

Answer 1

Solution:

A confidence interval is ( 66.1 , 301.5 )

Upper limit = 301.5

Lower limit = 66.1

Interval is nothing but Point estimate M.E.

i.e. M.E.

Upper Limit = + Margin of error

Lower Limit = - M.E.

Sample mean = (Upper limit + Lower limit)/2

= (301.5 + 66.1)/2

= 183.8

M.E. = (Upper limit - Lower limit)/2

= (301.5 - 66.1)/2

= 117.7

So , given interval can be written in M.E. form as

183.8 117.7