A researcher wants to determine if college students typically drink more than 3 times per week. She collects data on 125 college students. From the sample, she finds that they drank an average of 3.5 times per week, with a standard deviation of 2.3 drinks. Use a 5% significance level for any testing. Based on the scenario above, which of the following is TRUE regarding the type of test that would need to be performed? a. It is a two-tailed test.
b. It must be completed using the critical value approach.
c. It is a one-tailed test.
d. We reject the null and prove our claim.
e. We would need to estimate the significance level from the data.
f. Hypothesis testing cannot be performed on percentages.

Farmers know that driving heavy equipment on wet soil compresses the soil and injures future crops. here are data on the "penetrability" of the same type of soil at two levels of compression. penetrability is a measure of how much resistance plant roots will meet when they try to grow through the soil. compressed soil 2.85 2.66 3 2.82 2.76 2.81 2.78 3.08 2.94 2.86 3.08 2.82 2.78 2.98 3.00 2.78 2.96 2.90 3.18 3.16 intermediate soil 3.17 3.37 3.1 3.40 3.38 3.14 3.18 3.26 2.96 3.02 3.54 3.36 3.18 3.12 3.86 2.92 3.46 3.44 3.62 4.26 use the data, omitting the high outlier, to give a 95% confidence interval for the decrease in penetrability of compressed soil relative to intermediate soil. compute degrees of freedom using the conservative method. interval: to