Topics › Statistics › Discrete Random Variables — Mean and Standard Deviation
Statistics · PROB

Discrete Random Variables — Mean and Standard Deviation

A bar graph shows numbers as bars. Taller bar = bigger number.

StatisticsCommon Core VAR-5.APROBVerified correct ✓

Worked examples

A discrete random variable X has the following probability distribution: P(X=3) = 3/8, P(X=9) = 1/8, P(X=10) = 1/8, P(X=11) = 3/8. Calculate the expected value E(X).
Answer: 7.625
A discrete random variable X has the following probability distribution: P(X=1) = 1/8, P(X=2) = 5/8, P(X=6) = 1/8, P(X=9) = 1/8. Calculate the expected value E(X).
Answer: 3.25

Every problem on Pounce is generated and checked by code — never a wrong answer key.

Master Discrete Random Variables — Mean and Standard Deviation

Code-verified problems at exactly the right level, explained the way your kid learns.

Start your free trial 🐾

Build up to this

Expected Value — Discrete Probability DistributionsProbability Rules — Addition Rule and Complement

More Statistics topics

Frequency Tables — Relative Frequency and Marginal DistributionsCompare Distributions — Shape, Center, Spread, and Outliers (SOCS)Dot Plots and Histograms — Construct and InterpretBoxplots and the Five-Number SummaryMean and Standard Deviation — Compute and InterpretStandardized Scores (z-scores) — Position Within a DistributionNormal Distribution — The 68-95-99.7 Empirical RuleNormal Probability Calculations Using z-tables