MATH225N Week 8: Correlation and Causation

Description

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?

SOLUTION:

Correlation and Causation

Big Picture: Correlation vs. Causation

Correlation describes the direction and strength of a linear relationship between two quantitative variables. A positive correlation means that as one variable increases, the other tends to increase, while a negative correlation means that as one variable increases, the other tends to decrease. However, correlation does not prove causation. Causation requires evidence that one variable directly influences the other, which is usually established through strong study designs such as controlled experiments (Triola, 2018).……………………………………Get a complete solution at $ 9.9