A researcher was interested in understanding reproductive health among youth. She randomly selected a group of young persons and administered a questionnaire to collect information. The following table provides data on 10 respondents with their responses to selected questions.

Respondent #	Age of Respondent	Gender	Number of persons had sex with in the past 12 months	Economic Class
1	22	Female	3	Middle class
2	15	Male	0	Lower class
3	16	Male	1	Upper class
4	19	Male	2	Upper class
5	20	Female	2	Lower class
6	18	Female	1	Middle class
7	20	Male	3	Middle class
8	20	Female	0	Upper class
9	17	Female	2	Lower class
10	19	Male	0	Middle class

a. Indicate the most appropriate measure of central tendency for each variable listed and give a reason for your choice. (8 marks)

b. One of your classmates wanted to represent the variable Economic Class using a histogram. Explain to her why this is an appropriate or an inappropriate way to describe this variable. If inappropriate, suggest a more appropriate way to represent this information. (3 marks)

c. Suppose the researcher wants to investigate the mean number of sex partners in the past 12 months for young persons. It is believed that the mean number of sex partners was at least 2 persons in the past 12 months. Take this researcher through the steps involved in checking that this claim is true. Make sure to design your process to fit this particular situation. You do not need to calculate anything here. (7 marks) 2

2. A researcher studied the relationship between people’s knowledge about HIV/AIDS and their practice of safer sex. A group of 300 sexually active university students completed the AIDS Risk Knowledge Test. The test is marked out of 18 with higher scores indicating more awareness or knowledge of the risks associated with HIV/AIDS. Subjects also completed a survey about their sexual behaviour in the past six months. The researchers then classified these behaviours as high risk (for contracting HIV/AIDS) or low risk. The results showed that for the knowledge test, the mean was 11.15 and the standard deviation was 3.14. For the number of high-risk behaviours people had engaged in during the past six months, the mean was 15.38 and the standard deviation was 8.18. Were students more variable in their knowledge or in high-risk behaviours? Provide an explanation for your findings using appropriate statistics. (6 marks)

3. A researcher is interested in how much time all college students spend on social media sites. She conducted a study in which she asked 68 randomly selected college students how many hours per week they spent on social media sites. The average was 10.19 hours per week with a standard deviation of 2.56 hours per week. a. Construct a 95% confidence interval for the mean amount of time college students spend per week on social media sites and briefly interpret this interval. (6 marks)

b. Explain two ways in which the confidence interval above may change if constructed by another researcher. (4 marks)

4. According to a study by the Centers for Disease Control, the national mean hospital stay after childbirth is 2 days. Reviewing the records at her own hospital, a hospital administrator calculated that the mean hospital stay for a sample of 81 women after childbirth was 2.2 days with a standard deviation of 1.2 days. Assuming that the patients represent a random sample of the population, test the claim that the mean hospital stay at this hospital is different from the national average. Use a level of significance of 5%. (10 marks)