Question

Intrigued by a 2013 study at the University of Nebraska that suggested marijuana smokers may be thinner than other adults, a group of students did a project to explore the relationship between body mass index (BMI) and amount of time spent under the influence of marijuana (measured in hours per week). Based on a random sample of 33 students at their university, they used BMI as the response variable. The equation of the least-squares regression line is: hours per month under influence = 49.2−1.15 BMI. Also, r2=0.134 .

Answer 1

this question is incomplete, the complete question is:

1. is this model effective

2. what is the correlation coefficient for this data.

3. for a student with a bmi of 25, what is the predicted number of hours under the influence.

Explanation:

1. first of all this model is not effective because we have r² as 0.134. this tells us that only 13.4 percent of the of the variations that exist in this data has been explained by the model

1. we get the correlation coefficient by

`+-\sqrt{r^(2) }`

the regression slope coefficient has a negative sign. this is what we would use in calculating the correlation coefficient.

`-\sqrt{r^(2) }`

= -√0.134

= -0.366

therefore the correlation coefficient is -0.366

2. to get the number of hours under the influence with a bmi of 25

the equation is

49.2-1.15bmi

= 49.2-1.15(25)

= 49.2-28.75

= 20.45