Question

Question 1. For each of the following five scenarios, identify (a) the individuals, (b) the type of each variable according to its measurement, (c) the response and explanatory variables and (d) and whether the study is an experiment or an observational study. There is no need to explain your answers. Scenario A. It is posited that babies born at different times of the year may develop the ability to crawl at different ages. Thirty two babies born in January crawled at an average age of 29.75 weeks, with a standard deviation of 7 weeks. Another 32 babies born in August crawled at an average of 33.5 weeks with a standard deviation of 7 weeks. Scenario B. One hundred students in a large statistics class at a university were asked to describe their political position and whether they had engaged in binge drinking. Do people who engage in binge drinking tend to have certain political positions? Scenario C. Researchers timed 20 subjects as they tried to complete paper-andpencil mazes. Each subject attempted a maze both with and without the presence of a floral aroma. Subjects were randomized with respect to whether they did the scented trial first or second. Is there any evidence that the floral scent improved the subjects’ ability to complete the mazes? Scenario D. Given that postsecondary education in France is essentially free and that postsecondary education in the US is very expensive, a researcher wonders whether the total number of education years for French people is higher than that of Americans. Randomly chosen people in France and the US are asked for their number of years of education. Scenario E. Computers in some vehicles calculate various quantities related to performance. One of these is the fuel efficiency. For 50 randomly sampled vehicles equipped in this way, the number of liters per 100 kilometers driven were recorded.

Answer 1

Scenario A:

(a)Here individuals are the babies..

(b)variable : The time a baby takes to crawl.. quantitative variable.. unit : week.

(c)here only one variable is present.

(d)this study is observational study.

Scenario B:

(a) Students in the class of statistics of the university are the individuals.

(b) The variables are 'political position of a student' and 'engagement in binge drinking '.. both the variables are qualitative.

(c) Explanatory variable : engagement in binge drinking

Response variable : political position of a student.

(d) the study is an experiment.

Scenario C :

(a) The individuals here are the subjects.

(b) variables :'presence or absence of floral aroma' and ''attempting the maze''. Both variables are quantitative.

(c) Explanatory variable : Presence or absence of floral aroma

Response variable: completing the maze.

(d)The study is an experiment.

Scenario D:

(a) Individuals are randomly chosen people in France and US

(b) variables are : number of education years in France and US. The variables are quantitative. Unit: year.

(c) there is one type of variable in this situation.. and given above.

(d)the study is an observational study.

Scenario E:

(a) The individuals are vehicles.

(b) variable of interest is fuel efficiency. This is a quantitative variable. Unit: litre/10 km.

(c) only obe variable present . Already named above.

(d) The study is an observational study.