A soil scientist is interested in studying the pH level in the soil for a certain field. In particular, she is going to examine a random sample of soil samples and measure their pH levels to assess if the mean field pH level is neutral (that is, equal to 7) versus the alternative hypothesis that the mean pH level is acidic (that is, less than 7).

Let's Do It! 10.10

FEEDBACK

State the null and alternative hypotheses.

Suppose that it is reasonable to assume that the pH levels of all the possible samples that might be drawn are normally distributed. The scientist takes five randomly selected samples of soil from the field and measures the pH level in these samples. The pH levels in the sample were: 5.8, 6.3, 6.9, 6.2, 5.5. First calculate the sample mean and sample standard deviation, and then the value of the test statistic?

What is the p-value for this test?

Give your decision using a = 0.05.