Question

The population standard deviation for the heights of dogs, in inches, in a city is 3.4 inches. If we want to be 90% confident that the sample mean is within 1 inch of the true population mean, what is the minimum sample size that can be taken?

Answer 1

Answer:

The minimize size that can be taken is - 31.28 or 31 .

Step-by-step explanation:

Lets calculate -

    Population standard deviation, $\sigma=3.4 inches$

    Margin of error, E = 1

    Critical value , $z_0_._0_5 =1.645$

Now , the size of the sample , $n=(\frac{z\times \sigma}{E} )^2$

   Putting the given values ,

                    $=(\frac{1.645\times 3.4}{1})^2$

                  = 31.28 or 31 .

The given table of the question has been attached here .

Hence , the answer is 31.