contestada

A random sample of 100 automobiles traveling on a section of an interstate showed an average speed of 60 mph. the distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 13.5 mph. refer to exhibit 8-3. if we are interested in determining an interval estimate for μ at 90.0% confidence, the z value to use is

Respuesta :

The [tex] (1-\alpha )100\% [/tex] confidence interval for mean is

[tex] \mu \pm z_{\alpha/2} \frac{\sigma}{\sqrt{n} } [/tex].

Here [tex] \alpha =0.1 [/tex].

Use standard normal distribution table.

The z value to be used is such that

[tex] P(Z<z)=\alpha /2 [/tex]

[tex] P(Z<z)=0.05 [/tex]

z=-1.96

The z value to be used is 1.96.

Otras preguntas