Statistical Concepts and Inference 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 Statistical Concepts and Inference flashcards as text
For a strongly right-skewed income distribution, which measure of central tendency best represents a typical value?
Answer: Median
The median is resistant to extreme values and better reflects the typical observation in skewed data.
A correlation coefficient of -0.9 indicates:
Answer: A strong negative linear relationship
A coefficient near -1 indicates a strong negative linear association.
Which statement about correlation and causation is correct?
Answer: Correlation can arise from a confounding variable without direct causation
Two variables can be correlated due to a lurking confounder rather than one causing the other.
In a normal distribution, approximately what percentage of values fall within two standard deviations of the mean?
Answer: 95%
The empirical rule states about 95% of data lies within two standard deviations of the mean.
A z-score of 0 means the observation is:
Answer: Exactly at the mean
A z-score of 0 indicates the value equals the mean.
Which sampling method gives every member of the population an equal chance of selection?
Answer: Simple random sampling
Simple random sampling ensures each unit has an equal and independent probability of selection.
The interquartile range (IQR) measures:
Answer: The spread of the middle 50% of the data
The IQR is the distance between the 25th and 75th percentiles, capturing the central half of the data.