What does a Pearson Correlation Coefficient of 0 indicate?
- No correlation
- Perfect negative correlation
- Perfect positive correlation
- Weak positive correlation
A Pearson correlation coefficient of 0 indicates no correlation. This means that the variables are independent and there is no linear relationship between them.
How is the test statistic computed in the Sign Test?
- By averaging the ranks
- By counting the number of positive and negative signs
- By summing the differences
- By summing the ranks
In the Sign Test, the test statistic is computed by counting the number of positive and negative signs of the differences between paired observations.
In a box plot, the 'box' represents the ________ quartile range of the data.
- Full
- Inter
- Lower
- Upper
The 'box' in a box plot represents the interquartile range (IQR) of the data. This is the range within which the middle 50% of the data falls, calculated as the difference between the third quartile (Q3) and the first quartile (Q1).
The distribution of the sample mean will approach a normal distribution as the sample size increases, according to the _________.
- Central Limit Theorem
- Law of Large Numbers
- Probability Rule
- Sampling Distribution
According to the Central Limit Theorem, the distribution of the sample mean will approach a normal distribution as the sample size increases. Regardless of the shape of the population, the distribution of sample means taken with large enough sample size can be approximated by a normal distribution.
How can one adjust for multicollinearity in a multiple linear regression model?
- By adding interaction terms
- By increasing the sample size
- By removing one of the correlated variables or combining the correlated variables
- By transforming the dependent variable
To adjust for multicollinearity in a multiple linear regression model, one of the common strategies is to remove one of the highly correlated independent variables or to combine the correlated variables.
How does the effect size relate to the power of a t-test?
- Effect size has no relation to the power of a test
- Larger effect sizes are associated with higher power
- Larger effect sizes are associated with lower power
- nan
The effect size is the magnitude of the difference between groups. Larger effect sizes are easier to detect and are associated with higher power in a t-test.
What is the value of the probability of an impossible event?
- 0
- 0.5
- 1
- The probability is undefined
By definition, the probability of an impossible event is 0. This is because the measure of probability assigns 0 to events that cannot occur and 1 to events that are certain to occur.
_________ is a condition in which the error term in a regression model is correlated with itself.
- Autocorrelation
- Homoscedasticity
- Multicollinearity
- Underfitting
Autocorrelation, also known as serial correlation, is the correlation of a signal with a delayed copy of itself as a function of delay. In the context of a regression analysis, it refers to the condition when the error term (residuals) in a regression model is correlated with itself.
How is the F-statistic calculated in an ANOVA test?
- It is the difference between between-group variance and within-group variance
- It is the ratio of between-group variance to within-group variance
- It is the ratio of within-group variance to between-group variance
- It is the sum of between-group variance and within-group variance
In an ANOVA test, the F-statistic is calculated as the ratio of the between-group variance (mean sum of squares between groups) to the within-group variance (mean sum of squares within groups). A larger F-statistic implies a greater degree of difference between the group means.
What is the difference between excess kurtosis and kurtosis?
- Excess kurtosis is always greater than kurtosis
- Excess kurtosis is always less than kurtosis
- Excess kurtosis is kurtosis minus 3
- There is no difference between excess kurtosis and kurtosis
The difference between kurtosis and excess kurtosis comes down to a constant. Excess kurtosis is simply kurtosis minus 3. The "3" comes from the kurtosis of a normal distribution which is 3. Hence, excess kurtosis refers to kurtosis in relation to a normal distribution.