The _________ test is a non-parametric test that compares the medians of two paired groups.
- Chi-square
- Mann-Whitney U
- Sign
- Wilcoxon Signed Rank
The Wilcoxon Signed Rank test is a non-parametric test that compares the medians of two paired groups.
Why is interval estimation generally preferred over point estimation?
- Because it gives more accurate results
- Because it is easier to calculate
- Because it is less affected by outliers
- Because it provides a range of possible values rather than a single point
Interval estimation is generally preferred over point estimation because it provides a range of possible values rather than a single value. This range of values gives a better understanding of the uncertainty around the estimate, hence, it provides more information than a single point estimate.
Spearman's Rank Correlation is especially useful when the relationship between variables is ________, but not necessarily linear.
- Bimodal
- Monotonic
- Negative
- Positive
Spearman's Rank Correlation is especially useful when the relationship between variables is monotonic, but not necessarily linear. A monotonic relationship is one where the variables tend to change together, but not necessarily at a constant rate.
If the null hypothesis is true in ANOVA, the F-statistic follows a ________ distribution.
- Binomial
- Chi-Square
- F
- Normal
In ANOVA, if the null hypothesis is true, the F-statistic follows an F-distribution. The F-distribution is a probability distribution that is used most commonly in Analysis of Variance.
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.
In a normal distribution, about 95% of the data lies within _______ standard deviations of the mean.
- Four
- One
- Three
- Two
According to the empirical rule (also known as the 68-95-99.7 rule), in a normal distribution, about 68% of the data lies within one standard deviation of the mean, about 95% lies within two standard deviations, and about 99.7% lies within three standard deviations.
How do you diagnose multicollinearity in a multiple linear regression model?
- By calculating the R-squared value
- By checking the correlation matrix and Variance Inflation Factor (VIF)
- By looking at the residual plot
- By looking at the scatter plot
Multicollinearity is diagnosed in a multiple linear regression model by checking the correlation matrix and the Variance Inflation Factor (VIF). A high correlation between independent variables and a VIF greater than 5 or 10 suggests the presence of multicollinearity.
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.