What does the Wilcoxon Signed Rank Test compare in paired samples?
- Means
- Medians
- Modes
- Variance
The Wilcoxon Signed Rank Test compares the medians in paired samples.
What is the difference between correlation and causation?
- Causation implies correlation
- Correlation and causation are independent of each other
- Correlation implies causation
- Correlation means there is no causation
While correlation simply implies a relationship between two variables, causation goes a step further to explain that one variable actually causes the other to change. It's important to remember that correlation does not imply causation. However, if there is causation, there's likely to be correlation.
The correlation coefficient is denoted by the letter __.
- C
- P
- R
- S
The correlation coefficient is often denoted by the letter 'R'. In the case of Pearson's correlation, it's specifically denoted as 'r'. It measures the degree of relationship between two variables.
________ data is data that can be organized or ranked in a specific order.
- Continuous
- Discrete
- Nominal
- Ordinal
Ordinal data is a type of categorical data that can be organized or ranked in a specific order. For example, customer satisfaction ratings (satisfied, neutral, dissatisfied) can be organized from most to least satisfied.
How do you interpret the coefficients of interaction terms in a regression model?
- The interaction coefficient indicates the effect of one variable at a specific level of the other variable
- The interaction coefficient indicates the joint effect of the variables, independent of their individual effects
- The interaction coefficient is a measure of the correlation between the variables
- The interaction coefficient represents the average effect of two variables
The interaction coefficient in a regression model indicates the effect of one independent variable on the dependent variable for a specific level of another independent variable. It signifies that the effect of one variable depends on the value of another variable, thus capturing the interaction effect between the two variables.
A _______ test is used when the population variance is known.
- Chi-square
- F
- T
- Z
A Z-test is used when the population variance is known. It's based on the standard normal distribution.
The closer the correlation coefficient is to __ or __, the stronger the correlation.
- -1 or 1
- 0
- 0.5 or -0.5
- 1 or 2
The correlation coefficient measures the strength and direction of a linear relationship between two variables. It ranges from -1 to 1, with -1 indicating a perfect negative correlation, 1 indicating a perfect positive correlation, and 0 indicating no correlation. Thus, the closer the correlation coefficient is to -1 or 1, the stronger the correlation.
The number of trials in a binomial distribution is ________, whereas in a Poisson distribution, it's theoretically infinite.
- dependent on the sample size
- dependent on the success rate
- fixed
- infinite
In a binomial distribution, the number of trials is fixed (a fixed number of independent trials are considered), whereas in a Poisson distribution, theoretically, an infinite number of events can occur.
How do non-parametric statistical methods deal with outliers compared to parametric methods?
- They are more robust to outliers
- They are more sensitive to outliers
- They don't handle outliers
- They eliminate outliers before analysis
Non-parametric statistical methods are more robust to outliers compared to parametric methods. This is because non-parametric tests often use medians and ranks, which are less sensitive to extreme values, compared to means which are used in parametric tests.
What is the measure of central tendency that divides a data set into two equal halves?
- Mean
- Median
- Mode
- Range
The median is the measure of central tendency that divides a data set into two equal halves. When the observations are ordered from smallest to largest, the median is the middle value, ensuring that 50% of the data falls below and 50% above the median value.