1. The World Health Organization wishes to estimate the mean density of people per square kilometer, they collect data on 56 countries. Justify for full credit.

(a) Which of the following is the variable?

(i) All countries in the world(ii) Density of people per square kilometer(iii) Set of densities of people per square kilometer of all countries(iv) Set of densities of people per square kilometer of 56 countries

(b) Which of the following is the population?

(i) All countries in the world(ii) Density of people per square kilometer(iii) Set of densities of people per square kilometer of all countries(iv) Set of densities of people per square kilometer of 56 countries

2. Choose the best answer. Justify for full credit.

(a) A marketing agent asked people to rank the quality of a new soap on a scale from 1(poor) to 5 (excellent). The level of this measurement is:(i) interval(ii) nominal(iii) ordinal(iv) ratio

(b) A STAT 200 instructor surveyed nearly 100 students, who took STAT 200 in Fall2018, and asked how many hours they spent on STAT 200 each week. The average hoursspent was 12.25 hours. The value 12.25 is a:(i) parameter(ii) statistic(iii) population(iv) sample

5. A study of 10 different weight loss programs involved 500 subjects. Each of the 10 programs had 50 subjects in it. The subjects were followed for 12 months. Weight change for each subject was recorded. The researcher wants to test the claim that all ten programs are equally effective in weight loss.

(a) Which statistical approach should be used?(i) confidence interval(ii) t-test(iii) ANOVA(iv) Chi square

(b) Explain the rationale for your selection in (a). Specifically, why would this be theappropriate statistical approach?

6. A study was conducted to determine whether the mean braking distance of four-cylinder cars is greater than the mean braking distance of six-cylinder cars. A random sample of 20 fourcylinder cars and a random sample of 20 six-cylinder cars were obtained, and the braking distances were measured.

(a) What would be the appropriate hypothesis test for this analysis?(i) t-test for two independent samples(ii) t-test for dependent samples(iii) z-test for population mean(iv) correlation

(b) Explain the rationale for your selection in (a). Specifically, why would this be theappropriate statistical approach?