Correlation and simple linear regression

Question 1

What is a scatterplot?

Answer 1

A graph used to visually display the relationship between two continuous variables.

Question 2

What does each point on a scatterplot represent?

Answer 2

An observation in the dataset, with the x-coordinate representing one variable and the y-coordinate representing another.

Question 3

What does a positive correlation in a scatterplot suggest?

Answer 3

As one variable increases, the other also tends to increase.

Question 4

What is the independent variable in a scatterplot?

Answer 4

The predictor or causal variable, typically represented on the x-axis.

Question 5

What is the dependent variable in a scatterplot?

Answer 5

The outcome or response variable, typically represented on the y-axis.

Question 6

What is hypothesis testing?

Answer 6

A method to make inferences about population parameters based on sample data.

Question 7

What type of test is used for comparing means between two independent groups?

Answer 7

Independent t-test.

Question 8

What does Pearson’s χ² test assess?

Answer 8

The independence between two categorical variables.

Question 9

What are continuous variables?

Answer 9

Numerical data that can take any value within a range, such as height or weight.

Question 10

What are categorical variables?

Answer 10

Data that can be divided into distinct categories, such as gender or smoking status.

Question 11

What does correlation measure?

Answer 11

The strength and direction of the linear relationship between two continuous variables.

Question 12

What is linear regression used for?

Answer 12

To predict the value of one variable based on the value of another.

Question 13

What is a line of best fit?

Answer 13

A line that minimizes the distance between each data point and the line itself, representing the trend in the data.

Question 14

What does a positive trend in a scatterplot indicate?

Answer 14

Points slope upward from left to right, indicating a positive relationship.

Question 15

What does a negative trend in a scatterplot indicate?

Answer 15

Points slope downward from left to right, indicating a negative relationship.

Question 16

What is a spurious correlation?

Answer 16

A misleading statistical association between variables caused by an unseen third variable or random chance.

Question 17

Fill in the blank: The correlation coefficient is denoted as _____ and ranges from -1 to +1.

Answer 17

r

Question 18

What is Pearson’s Correlation Coefficient used for?

Answer 18

To measure the linear relationship between two continuous, normally distributed variables.

Question 19

What does a strong positive correlation range from?

Answer 19

0.60 to 0.79.

Question 20

What is the Ordinary Least Squares (OLS) method?

Answer 20

A method used to find the best-fitting line in simple linear regression by minimizing the sum of squared residuals.

Question 21

How do you interpret an R² value of 0.27?

Answer 21

27% of the variance in the outcome can be explained by the predictor variable.

Question 22

What are dummy variables?

Answer 22

Variables created to include categorical predictors in regression analysis, typically coded as 0 and 1.

Question 23

What is the first step in generating scatterplots in SPSS?

Answer 23

Load the dataset.

Question 24

What is the purpose of interpreting scatterplots?

Answer 24

To assess the pattern of the points and identify relationships.

Question 25

What are the types of statistical tests used for hypothesis testing?

Answer 25

• t-tests
• Chi-Square Test (χ²)
• Pearson’s χ² test
• McNemar Test

Question 26

What is the role of independent and dependent variables in research?

Answer 26

Independent Variable (IV): Predictor; Dependent Variable (DV): Outcome.

Question 27

What is a practical application of correlation analysis in psychology?

Answer 27

Investigating the correlation between hours of sleep and cognitive performance scores.

Question 28

True or False: A scatterplot can only show linear relationships.

Answer 28

False