Correlation and simple linear regression Flashcards
What is a scatterplot?
A graph used to visually display the relationship between two continuous variables.
What does each point on a scatterplot represent?
An observation in the dataset, with the x-coordinate representing one variable and the y-coordinate representing another.
What does a positive correlation in a scatterplot suggest?
As one variable increases, the other also tends to increase.
What is the independent variable in a scatterplot?
The predictor or causal variable, typically represented on the x-axis.
What is the dependent variable in a scatterplot?
The outcome or response variable, typically represented on the y-axis.
What is hypothesis testing?
A method to make inferences about population parameters based on sample data.
What type of test is used for comparing means between two independent groups?
Independent t-test.
What does Pearson’s χ² test assess?
The independence between two categorical variables.
What are continuous variables?
Numerical data that can take any value within a range, such as height or weight.
What are categorical variables?
Data that can be divided into distinct categories, such as gender or smoking status.
What does correlation measure?
The strength and direction of the linear relationship between two continuous variables.
What is linear regression used for?
To predict the value of one variable based on the value of another.
What is a line of best fit?
A line that minimizes the distance between each data point and the line itself, representing the trend in the data.
What does a positive trend in a scatterplot indicate?
Points slope upward from left to right, indicating a positive relationship.
What does a negative trend in a scatterplot indicate?
Points slope downward from left to right, indicating a negative relationship.
What is a spurious correlation?
A misleading statistical association between variables caused by an unseen third variable or random chance.
Fill in the blank: The correlation coefficient is denoted as _____ and ranges from -1 to +1.
r
What is Pearson’s Correlation Coefficient used for?
To measure the linear relationship between two continuous, normally distributed variables.
What does a strong positive correlation range from?
0.60 to 0.79.
What is the Ordinary Least Squares (OLS) method?
A method used to find the best-fitting line in simple linear regression by minimizing the sum of squared residuals.
How do you interpret an R² value of 0.27?
27% of the variance in the outcome can be explained by the predictor variable.
What are dummy variables?
Variables created to include categorical predictors in regression analysis, typically coded as 0 and 1.
What is the first step in generating scatterplots in SPSS?
Load the dataset.
What is the purpose of interpreting scatterplots?
To assess the pattern of the points and identify relationships.
What are the types of statistical tests used for hypothesis testing?
- t-tests
- Chi-Square Test (χ²)
- Pearson’s χ² test
- McNemar Test
What is the role of independent and dependent variables in research?
Independent Variable (IV): Predictor; Dependent Variable (DV): Outcome.
What is a practical application of correlation analysis in psychology?
Investigating the correlation between hours of sleep and cognitive performance scores.
True or False: A scatterplot can only show linear relationships.
False
