please help me!!!!

[jaimetab]

The Ford Taurus was listed as having a highway fuel efficiency of 30 mpg (1995 Motor Trend New Car
Buyer’s Guide). A consumer interest group conducts automobile mileage tests seeking statistical
evidence to show that automobile manufacturers overstate the miles per gallon ratings for particular
models. In a sample of 50 mileage tests with the Ford Taurus, the consumer interest group finds a
sample mean highway rating of 29.5 mpg. Assume a population standard deviation of 1.8 mpg. What
conclusion can be drawn from these results? Use the p?value approach with a 1% level of significance.

 

[galactus]

Just use the formula \(\displaystyle z=\frac{(x-{\mu})\sqrt{n}}{{\sigma}}\)

Find your test statistic. Look up the critical value for 1% alpha level. It is -2.3263

\(\displaystyle H_{0}:{\mu}\geq \;\ 30\)

\(\displaystyle H_{a}:{\mu}< \;\ 30 \;\ \text{claim}\)...........left-tailed test.

Are you in the rejection region?. That is, is the test statistic less than the critical value?. If it is, then reject.

But, the problem says use the p-value to decide. If the p-value is greater than the alpha level, then do not reject.

If it is less than the alpha level, then reject.

The p-value is .0276

 

[stephenxanders]

Very nice Solution Galactus