MATH225N Week 8: Correlation and Causation

CLASS:

MATH225N – Statistical Reasoning for the Health Sciences

MATH225N Week 8: Correlation and Causation

Question

An experiment finds that runners with the longest legs complete a mile run in less time.

Identify the relation between leg length and time of a mile run.

The y-intercept is −4815, which is not feasible because a product cannot have a negative cost.

Answer:

Leg length and time of a mile run are negatively correlated.

Question

Which of the following situations could have a regression line with a negative y-intercept? Select all that apply.

Correct answer:

The profit (sales price minus cost) made selling a unit in terms of number of units produced.

The value of a Fortune-500 company, founded in the year 1990,  as a function of the number of years since founding.

Question

The scatter plot below shows the average cost of a designer jacket in a sample of years between 2000 and 2015. The least squares regression line modeling this data is given by yˆ=−4815+3.765x.

Interpret the y-intercept of the least squares regression line. Is it feasible?

Ans:

The y-intercept is −4815, which is not feasible because a product cannot have a negative cost………………….please purchase all the questions and answers at $10 only