What you’ll learn
Calculate joint, marginal and conditional frequencies.
Key idea
Joint and marginal relative frequencies use the whole sample; conditioning restricts the denominator to its named group.
Joint and marginal shares use the full sample; conditioning uses its named row and all three ordered values must be correct.
Worked example
Enter the exact value or ordered values in the format requested below.
Sports [Yes 4, No 6, total 10]; Music [Yes 3, No 7, total 10]; the exclusive groups total 20. Enter THREE exact numerical shares separated by commas, ordered: joint Sports&Yes; marginal Yes; conditional Yes among Sports.
- Joint Sports-and-Yes share uses 4/20=1/5; Yes marginal uses (4+3)/20=7/20.
- Conditional Yes among Sports uses 4/10=2/5; inverse joint count is 10×(2/5)=4. Keep reference groups distinct.
Answer: 1/5,7/20,2/5
Quick Check
Evaluate a worked attempt at calculate joint, marginal and conditional frequencies, identify the first invalid step, and provide the correction.
Sports [Yes 7, No 3, total 10]; Music [Yes 7, No 3, total 10]; the exclusive groups total 20. Step 1 identifies Sports-and-Yes count 7 correctly. Step 2 reports joint 7/10, marginal 7/10, conditional 7/20, swapping row and full-sample denominators. Identify first invalid step and correct the ordered three shares.