What is the primary purpose of inferential statistics?
To make generalizations about a population based on a sample.
To organize and clean raw data.
To visually represent data using graphs and charts.
To describe and summarize data.
Which of the following is NOT an assumption of a two-sample t-test?
The two groups are dependent on each other.
The data points within each group are independent.
The variances of the two groups are equal.
The data in each group are normally distributed.
What does an R-squared value of 0.80 indicate?
80% of the variation in the dependent variable is explained by the independent variable.
The slope of the regression line is 0.80.
20% of the variation in the dependent variable is explained by the independent variable.
The correlation between the variables is 0.80.
Which of the following statements is TRUE about multivariate analysis of variance (MANOVA)?
It tests the difference in means between two groups on a single dependent variable.
It is used for dimensionality reduction of categorical variables.
It examines the relationship between two continuous variables.
It analyzes the differences between groups on multiple dependent variables simultaneously.
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.
What is a Type II error in hypothesis testing?
Rejecting the null hypothesis when it is true.
Using the wrong test statistic for the data.
Incorrectly calculating the p-value.
Failing to reject the null hypothesis when it is false.
Which distribution is often used to model the time between events that occur independently and at a constant average rate?
Normal Distribution
Binomial Distribution
Exponential Distribution
Poisson Distribution
A moving average model is best suited for forecasting time series data with which characteristic?
Significant outliers
High volatility
A constant mean
Strong seasonality
If a residual plot shows a funnel shape (increasing spread of residuals as the predicted value increases), what does this indicate?
Homoscedasticity
Multicollinearity
Heteroscedasticity
Autocorrelation
You want to compare the average heights of men and women in a population. Which hypothesis test would be most appropriate?
Chi-square test
Paired t-test
One-sample t-test
Independent samples t-test