Question

A boxer would like to know the mean diameter of a navel orange. If the standard deviation is 0.3 inches, how many oranges would need to be in his sample for an error of at most 0.1 inch at 95% confidence? 34 24 35 25

Answer 1

Ans c) 35

Explanation:

Standard deviation $\sigma = 0.3$

Critical value at 95% confidence:

Margin of Error E = 0.1

$E = z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$

$n= \left [ \frac{z_{\alpha/2}\times\sigma}{E} \right ]^2$

$n= \left [\frac{1.96\times0.3}{0.1} \right ]^2$

ans.