On a test called the MMPI-2, a score of 30 on the Anxiety Subscale is considered very low. Felipe participates in a yoga group at his gym and decides to give this subscale to 18 people in his yoga group. The mean of their scores is 35.2, with a standard deviation of 10.4. He wants to determine whether their anxiety scores are statistically equal to 30.

a. What are the groups for this one-sample t-test?

b. What is the null hypothesis for this one-sample t-test?

c. What is the value of α?

d. Should the researcher conduct a one- or two-tailed test?

e. What is the alternative hypothesis?

f. What is the value for degrees of freedom?

g. What is the t-observed value?

h. What is(are) the t-critical value(s)?

i. Based on the critical and observed values, should Felipe reject or retain the null hypothesis? Does this mean that his yoga group has scores that are above 30, below 30, or statistically equal to 30?

j. What is the p-value for this example?

k. What is the Cohen’s d value for this example?

l. If the α value were dropped to .01, would Felipe reject or retain the null hypothesis?

m. Calculate a 42% CI around the sample mean.

n. Calculate a 79% CI around the sample mean.

o. Calculate a 95% CI around the sample mean.