Key Concepts | 2026 UPDATE WITH COMPLETE
SOLUTION
Interval - ANSWERS-Numerical scales with no true zero (it's still there; just
another number on the scale)
Ratio - ANSWERS-Numerical scales with a true zero (nothing is there; absent)
Normal Distribution/Bell Curve - ANSWERS-68.3% of data within 1 σ of the
mean, 95.4% of data within 2 σ of the mean, 99.7% of data within 3 σ of the
mean
Z-Score - ANSWERS-(Data point - Mean) / Standard Deviation
Probability Rules - ANSWERS-When they ask about the probabilities for
everything, then Multiply (intersection); when they do not ask about the
probabilities for everything, then Add (union)
Bayes - ANSWERS-When asked about an event happening given that another
event has already occurred
R-square - ANSWERS-Goodness of Fit that ranges from 0 Weak Fit to 1 Strong
Fit
Logistic Regression - ANSWERS-The dependent variable is binary (Yes/No or
On/Off)
Mean - ANSWERS-Average of all values