Questions about concepts in Exam 1

Question 1

What does the slope of a regresison line tell us?

Answer 1

How much the average value of Y changes per one unit change in x

Question 2

Which choice is not an appropriate term for the x variable in a regression equation?

Answer 2

It can be called an independent, predictor or explenatory but NOT dependent

Question 3

What is the best way to determine if there is a statistically significant linear relationship between 2 quanitative variables?

Answer 3

Conduct a test of the null hypothesis that the population slope is 0

Question 4

The R squared value is reported by researches to be 49%. Which of the following statments is correct?

Answer 4

The independent variable explains 49% of variability in the response variable

Question 5

What is the primary difference between a confidence interval and a prediction interval?

Answer 5

A confidence interval estimates the mean value of y at a particular value of x, while a prediction interval estimates the range of y values at one specific value of x.

Question 6

At what value is a prediction interval the narrowest?

Answer 6

The mean value of x

Question 7

What are the 4 residual assumptions that must be held for valid linear regression inference?

Answer 7

1. Normality 2.Homoscedasity 3. Linearity 4.Independence of Residuals

Question 8

When assessing the relationship of a plot what are things you must mention?

Answer 8

The type of relationship (positive or negative) and between which variables, the linearity(linear or non-linear) and strength(strong or weak)