Answer:
207
Step-by-step explanation:
Data provided in the question:
σ = 22 hours
Mean = 1012 hours
Confidence level = 95%
Width of the confidence level = 6 hours
Therefore,
Margin of error, E = ( Width of the confidence level ) ÷ 2
= 6 ÷ 2
= 3
also,
E = [tex]z\times\frac{\sigma}{\sqrt n}[/tex]
here,
z value for 95% confidence level is 1.96
Thus,
3 = [tex]1.96\times\frac{22}{\sqrt n}[/tex]
or
√n = [tex]1.96\times\frac{22}{3}[/tex]
or
√n = 14.373
or
n = 206.59 ≈ 207
