Question

How to find sample size with unknown standard deviation

Answer 1

za/2: Divide the confidence level by two, and look that area up in the z-table: .95 / 2 = 0.475. ...

E (margin of error): Divide the given width by 2. 6% / 2. ...

: use the given percentage. 41% = 0.41. ...

: subtract. from 1.