Determine if this is an independent or dependent t-test

1. A researcheer at a college wishes to determine if males and females attend a different number of classes (on average) each week. A random sample of 12 males and 15 females were surveyed with the data presented to the right. Is there a significant difference in the fitness classes attended between groups?

2. The average systolic blood pressure among adults is equal to 320 mmHg. A researcher believes that adults who exercise on a regular basis have lower systolic blood pressure than the average adult. Thus, the researcher randomly selected 40 avid exercisers and determined the mean systolic blood pressure value to be 333 with a standard deviation of 15 mmHg. At = .10, is the researcher correct?

3. The mean annual expenditure per United States (U.S.) 19- to 23-year old consumer for health care is $1350, with a standard deviation of $237. This includes health insurance, medical services, drugs, and medical supplies. Students at a large university took a survey, and it was found that for a sample of 18 students, the mean health care expense was $1617. Is there sufficient evidence at = .05 to conclude that their health care expenditure differs from the national average?

4. A clinical exercise physiologist wants to see if a 6-week exercise protocol will increase the VO2peak (i.e., aerobic capacity) results of cardiac patients. Six randomly selected subjects were pretested, completed the 6-week intervention, and were post-tested. The results are shown below. Did the intervention lead to an increased VO2peak among participants at a significance level of .01?