Analysis Flashcards
7 cards from real Data Science practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Analysis flashcards as text
A dataset of household incomes has a mean far higher than its median. What does this indicate?
Answer: Right (positive) skew
When the mean exceeds the median, a long right tail of high values pulls the mean up, indicating positive skew.
Which measure of central tendency is most robust to outliers?
Answer: Median
The median depends only on the middle value(s) and is unaffected by extreme observations.
You compute the interquartile range (IQR) to detect outliers. Which boundary commonly flags an outlier?
Answer: Below Q1 - 1.5*IQR or above Q3 + 1.5*IQR
The standard Tukey rule flags points beyond 1.5*IQR past the first or third quartile.
A correlation coefficient between two variables is -0.9. What does this describe?
Answer: A strong negative linear relationship
A value near -1 indicates a strong inverse linear association.
Which statement about correlation and causation is correct?
Answer: Correlation does not imply causation
Two variables can correlate due to confounders or coincidence without any causal link.
When summarizing a categorical variable, which is most appropriate?
Answer: Frequency counts or proportions
Categorical data is summarized by how often each category occurs, not by arithmetic averages.
A boxplot shows the box much wider on the upper half than the lower half. This suggests the data is:
Answer: Skewed toward higher values
An asymmetric box with a longer upper section indicates skew toward larger values.