Question

Find the minimum sample size n needed to estimate μ for the given values of​ c, σ​, and E.

c=0.95, σ=7.2, and E=1

Assume that a preliminary sample has at least 30 members.

n=___ (Round up to the nearest whole​ number.)

Answer 1

Solution:

Given: c=0.95, , E=1

We have to find sample size n.

Formula

We need to find Zc value for c=0.95 confidence level.

Thus find area=(1+c)/2=(1+0.95)/2=0.9750

Look in z table for area=0.9750 or its closest area and find corresponding z value.

Area =0.9750 corresponds to 1.9 and 0.06

Thus z =1.96

Thus we get

(Note: Sample size is always rounded up)