Gc. what sample size is needed so that the length of the interval is $60 with 95% confidence?

What sample size is needed so that the length of the interval is $60 with 95% confidence?  We Assume:   σ      =     $150.

Showing Work:

n   >  is the sample size we want to find:

N        =      ( z  a/2^σ / E )^2

=               ( 1.96   *     150 / 30 )^2        (margin of error is 1.96 times the standard error):

 >      96.04   ≈     97

Hope that helps                                        : )

step-by-step explanation:

once you graph it hit 2nd (the blue button) and graph

that takes you to a table of coordinates

on the left is x coordinates and on the right is y coordinates and an empty box

(you may have to scroll up/down in order to get ( x, 0)