A 98% confidence interval for the mean of a population is to be constructed and must be accurate to within 0.3 unit. A preliminary sample standard deviation is 1.7. The smallest sample size n that provides the desired accuracy is

Respuesta :

Answer:

[tex] n = (\frac{2.326*1.7}{0.3})^2= 173.73[/tex]

And the value for n rounded up would be n = 174

Step-by-step explanation:

We have the following info given:

[tex] s= 1.7[/tex] previous estimation for the deviation

[tex] ME=0.03[/tex] the margin of error desired

[tex] Conf =0.98[/tex] represent the confidence

The Margin of error is given by:

[tex] ME = z_{\alpha/2} \frac{\sigma}{\sqrt{n}}[/tex]

If we solve for the value of n we got:

[tex] n= (\frac{z*\sigma}{ME})^2[/tex]

For this problem we know that the confidence is 98% so then the significance level would be [tex]\alpha=0.02[/tex] and the critical value would be:

[tex] z_{\alpha/2}= 2.326[/tex]

And replacing we got:

[tex] n = (\frac{2.326*1.7}{0.3})^2= 173.73[/tex]

And the value for n rounded up would be n = 174