AP Statistics Condensed Cheat Sheet

Flashcards covering key concepts from AP Statistics, including definitions and essential formulas.

Mean

Average of data points.

Median

Middle value of ordered data.

Standard Deviation

Spread around the mean.

Interquartile Range (IQR)

Q3 - Q1.

Outlier Rule

< Q1 - 1.5IQR or > Q3 + 1.5IQR.

Skewed Right

When Mean > Median.

Skewed Left

When Mean < Median.

Scatterplot

Shows direction, form, strength of a relationship.

Correlation (r)

Strength and direction of linear relationship.

r²

Percentage of variation explained by regression line.

Residual

Actual - Predicted value.

Slope Interpretation

For each unit increase in x, y increases by slope.

Random Sample

Method that reduces bias in data collection.

Observational Study

Study with no treatment imposed.

Experiment

Study that includes random assignment to treatments.

Confounding

When variables are intertwined with treatment effects.

Blocking

Grouping by known variables in an experiment.

Placebo

A treatment that has no active ingredient, used to reduce bias.

Double-Blind

An experimental design in which neither participants nor administrators know who is receiving a treatment.

Probability of A and B

P(A and B) = P(A) * P(B) if independent.

Probability of A or B

P(A or B) = P(A) + P(B) - P(A and B).

Binomial Distribution

Fixed number of trials with success/failure and same probability p.

Geometric Distribution

Trials until the first success occurs.

Expected Value

Mean of random variable outcomes.

Central Limit Theorem (CLT)

Sampling distribution is approximately Normal if n ≥ 30.

Standard Error (mean)

Calculated as σ/√n.

Standard Error (proportion)

Calculated as √(p(1-p)/n).

Confidence Interval

Statistic ± margin of error.

Interpret Confidence Interval

We are ___% confident the true parameter is within this interval.

Hypothesis Test

Comparison of null hypothesis (H0) vs alternative hypothesis (Ha).

P-value

Probability of observing data or more extreme, assuming the null hypothesis is true.

Type I Error

Rejecting H0 when it is actually true.

Type II Error

Failing to reject H0 when it is actually false.

Conditions for Inference

Conditions must be Random, Normal, and Independent.