Question

Use StatCrunch for each of the following problems. Paste StatCrunch output, state the rejection rule, and give both parts of the conclusion.

A random sample of 425 residents of a city have finished an average of 12.7 years of schooling with a standard deviation of 7 years. In the state as a whole, we know the average years of schooling completed is 12.2 years. Test whether the average years of education in the city is higher than the average for the state as a whole.

Answer 1

The hypotheses are:

Since sample mean =12.7 and sample size, n=425 >>30 hence Z statistic is applicable

Test statistic:

P-value:

P-value according to the Z score is computed using Z table shown below as

=0.0708

Conclusion:

Since the P-value > 0.01, 0.05 but less than 0.1 hence at only 90 % confidence level we can reject the null hypothesis and supprt the claim,