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Linear Regression and Correlation in Two-Variable Data Quiz

#1

What does the correlation coefficient measure in linear regression?

The strength and direction of the linear relationship between two variables
Explanation

Correlation coefficient measures linear relationship strength and direction.

#2

Which of the following is a common method for estimating the parameters of a linear regression model?

Least squares estimation
Explanation

Least squares estimation is commonly used for parameter estimation in linear regression.

#3

What is the purpose of the coefficient of correlation in linear regression?

To measure the strength and direction of the linear relationship between two variables
Explanation

Coefficient of correlation measures linear relationship strength and direction.

#4

Which statement about the residuals in linear regression is true?

They represent the difference between the observed and predicted values of the dependent variable
Explanation

Residuals represent the deviation between observed and predicted dependent variable values.

#5

What is the formula for the slope (β₁) in simple linear regression?

β₁ = Σ(xy) / Σ(x^2)
Explanation

Slope in simple linear regression is calculated as Σ(xy) / Σ(x^2).

#6

Which of the following best describes the purpose of the intercept (β₀) in linear regression?

It represents the predicted value of the dependent variable when the independent variable is zero
Explanation

Intercept in linear regression represents predicted dependent variable value when independent variable is zero.

#7

In linear regression, what does the coefficient of determination (R-squared) indicate?

The proportion of the variance in the dependent variable that is predictable from the independent variable
Explanation

R-squared indicates the proportion of variance in the dependent variable predictable from the independent variable.

#8

What does it mean if the p-value associated with a coefficient in linear regression is less than the significance level (e.g., 0.05)?

The coefficient is statistically significant at the given significance level
Explanation

P-value < significance level indicates coefficient's statistical significance.

#9

What does multicollinearity refer to in the context of linear regression?

High correlation among independent variables
Explanation

Multicollinearity refers to high correlation among independent variables.

#10

Which of the following is NOT an assumption of linear regression?

Normality of the dependent variable
Explanation

Normality of the dependent variable is not an assumption of linear regression.

#11

In multiple linear regression, what does the adjusted R-squared measure?

The proportion of the variance in the dependent variable explained by the independent variables
Explanation

Adjusted R-squared measures the proportion of dependent variable variance explained by independent variables.

#12

What is the purpose of residual plots in linear regression analysis?

To detect patterns or trends in the residuals
Explanation

Residual plots identify patterns or trends in regression residuals.

#13

Which assumption of linear regression states that the residuals should be normally distributed?

Normality of residuals
Explanation

Normality of residuals is an assumption in linear regression.

#14

What is the purpose of residual analysis in linear regression?

To assess the validity of the regression assumptions
Explanation

Residual analysis evaluates the validity of regression assumptions.

#15

Which of the following regression techniques is suitable for modeling nonlinear relationships between variables?

Polynomial regression
Explanation

Polynomial regression is suitable for modeling nonlinear relationships.

#16

What assumption of linear regression states that the variance of the residuals should be constant across all values of the independent variable?

Homoscedasticity
Explanation

Homoscedasticity assumes constant variance of residuals across all independent variable values.

#17

What is the primary goal of transforming variables in regression analysis?

To make the relationship between variables more linear.
Explanation

Variable transformation aims to linearize the relationship between variables in regression analysis.

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