What does a Pearson correlation coefficient of -0.9 suggest about the relationship between two variables?
Weak positive linear relationship
Strong positive linear relationship
Strong negative linear relationship
No linear relationship
Which of the following is NOT a key assumption of the Central Limit Theorem?
The samples are independent and randomly selected.
The population distribution is normal.
The population has a finite mean and variance.
The sample size is sufficiently large (generally n ≥ 30).
When would you use a paired t-test instead of an independent t-test?
When comparing the means of two groups with unequal variances.
When comparing the means of two independent groups.
When comparing the means of three or more groups.
When comparing the means of the same group before and after a treatment.
Which of the following smoothing methods is most appropriate when the time series data exhibits a trend but no seasonality?
Triple Exponential Smoothing
Simple Exponential Smoothing
Moving Average Smoothing
Double Exponential Smoothing
Which of the following statements is TRUE about multivariate analysis of variance (MANOVA)?
It examines the relationship between two continuous variables.
It tests the difference in means between two groups on a single dependent variable.
It analyzes the differences between groups on multiple dependent variables simultaneously.
It is used for dimensionality reduction of categorical variables.
If the variance of a random variable is 9, what is its standard deviation?
18
9
3
81
In multiple regression, what does a high variance inflation factor (VIF) indicate?
Heteroscedasticity in the residuals
Low multicollinearity among predictor variables
A good fit of the regression model
High multicollinearity among predictor variables
An event has three possible outcomes: A, B, and C. You know P(A) = 0.2 and P(B) = 0.3. What is the value of P(C) according to the law of total probability?
0.7
0.3
0.5
Cannot be determined
A Chi-square test is used to:
Compare the means of two groups.
Analyze the variance within and between groups.
Analyze the relationship between two categorical variables.
Determine if a sample mean is significantly different from a known population mean.
What does an R-squared value of 0.80 indicate?
The correlation between the variables is 0.80.
20% of the variation in the dependent variable is explained by the independent variable.
80% of the variation in the dependent variable is explained by the independent variable.
The slope of the regression line is 0.80.