Which of the following is NOT an assumption of a two-sample t-test?
The variances of the two groups are equal.
The data in each group are normally distributed.
The two groups are dependent on each other.
The data points within each group are independent.
When is Spearman's rank correlation a more appropriate measure of association than Pearson's correlation?
When outliers are not present in the data
When the relationship between variables is non-linear but monotonic
When the variables are measured on an interval or ratio scale and normally distributed
When the relationship between variables is perfectly linear
In exponential smoothing, a higher value of the smoothing parameter (alpha) gives _______ weight to recent observations.
Higher
Lower
Zero
Equal
A high R² value in a regression analysis always indicates a good fit of the model. Is this statement true or false?
False
True
The sampling distribution of a statistic is:
The same as the population distribution.
The distribution of the statistic across all possible samples of a given size.
Always normally distributed.
The distribution of the statistic in a single random sample.
What is the null hypothesis in a Chi-square test of independence?
The two variables are independent.
The means of the two groups are equal.
The two variables are dependent.
You're playing a game where you flip a coin. Heads, you win $10. Tails, you lose $5. What is the expected value of playing this game?
-$2.50
$5.00
$2.50
$0.00
What is the range of the Pearson correlation coefficient?
0 to infinity
0 to 1
-1 to 0
-1 to 1
What does a residual in regression analysis represent?
The slope of the regression line
The intercept of the regression line
The correlation between the independent and dependent variables
The difference between the observed value and the predicted value of the dependent variable
What is the primary purpose of inferential statistics?
To visually represent data using graphs and charts.
To describe and summarize data.
To organize and clean raw data.
To make generalizations about a population based on a sample.