Using the z-distribution, it is found that since the p-value is less than 0.05, there is evidence to support the claim that the average cost of private universities are decreasing.
<h3>What are the hypothesis tested?</h3>At the null hypothesis, it is tested if the average cost is still of $50,000, that is:
At the alternative hypothesis, it is tested if the average cost is decreasing, that is:
The test statistic is:
In which:
is the sample mean.
is the value tested at the null hypothesis.
is the standard deviation of the population.
- n is the sample size.
The parameters for this problem are:
Hence:
z = -2.2.
<h3>What is the p-value and the conclusion?</h3>Using a z-distribution calculator, for a left-tailed test, as we are testing if the mean is less than a value, with z = -2.2, the p-value is of 0.0139.
Since the p-value is less than 0.05, there is evidence to support the claim that the average cost of private universities are decreasing.
More can be learned about the z-distribution at brainly.com/question/16313918
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