In _____ deletion, all data from a participant is discarded if any single value is missing.
- Listwise
- Pairwise
- Random
- Systematic
In 'listwise' deletion, all data from a participant is discarded if any single value is missing. It is the simplest form of dealing with missing data but can lead to significant loss of information if missing data is not completely at random.
A correlation coefficient of +1 between two variables indicates what kind of relationship?
- No relationship
- Perfect negative linear relationship
- Perfect positive linear relationship
- Weak relationship
A correlation coefficient of +1 between two variables indicates a perfect positive linear relationship. This means that if one variable increases, the other variable also increases at a constant rate, and vice versa.
You've 'explored' the data and drawn some conclusions, but upon 'communicating' your findings, stakeholders have additional questions. What would be the next step in the EDA process?
- Direct the stakeholders to the raw data
- Ignore the questions and conclude the analysis
- Revisit the questioning phase with these new questions
- Wrap up the communication phase quickly
In this situation, the next step should be to revisit the 'questioning' phase with these new questions from stakeholders. Additional questions from stakeholders might reflect aspects of the data that have not been covered or require further investigation. Revisiting the questioning phase will allow these aspects to be incorporated into the analysis.
What kind of distribution is indicated by a skewness of zero?
- A bimodal distribution.
- A negatively skewed distribution.
- A normal distribution.
- A positively skewed distribution.
A skewness of zero is indicative of a "Normal Distribution". In a perfect normal distribution, both tails are equal, so they balance each other out, and hence, the skewness is zero.
If missing data is not properly addressed, the model's ________ can be significantly affected.
- F1 score
- accuracy
- precision
- recall
If missing data is not handled correctly, it can lead to biases in the data, which can adversely affect the model's accuracy.
In a clinical trial, the average recovery time for a new drug is drastically increased due to a patient who took an unusually long time to recover. How would this patient's data point be classified in this context?
- A normal data point
- An error
- An outlier
- nan
This patient's data point would be classified as an outlier as it deviates significantly from the other data points.
What are the effects of outliers on the results of a hypothesis testing procedure?
- All of these
- Can affect the statistical significance
- Can lead to type I errors
- Can lead to type II errors
Outliers can affect the results of a hypothesis testing procedure in several ways. They can lead to Type I or Type II errors, and can also affect the statistical significance of the test, thereby potentially leading to incorrect conclusions.
What role does bin size play in outlier detection when using a histogram?
- Bin size can influence outlier detection
- Bin size does not influence outlier detection
- Larger bin size always increases outlier visibility
- Smaller bin size always increases outlier visibility
The bin size in a histogram can influence the visibility of outliers. Depending on how the data is binned, an outlier may or may not be clearly visible.
The mode is the only measure of central tendency that can be used for _____ data.
- Categorical
- Interval
- Numerical
- Ordinal
The "Mode" is the only measure of central tendency that can be used for "Categorical" data. This is because it simply represents the most frequently occurring category or value.
How does the presence of outliers affect the range and interquartile range?
- Decreases both
- Increases IQR, but doesn't affect range
- Increases both
- Increases range, but doesn't affect IQR
Outliers significantly affect the "Range" as it measures the distance between the largest and smallest values. However, the Interquartile Range (IQR), being a measure of the middle 50% of the data, is not affected by outliers.