Proportion

Definition

A proportion is a type of ratio that compares a part to the whole, often expressed as a fraction, decimal, or percentage. In statistics, it represents how frequently an event occurs relative to the total number of trials.

5 Must Know Facts For Your Next Test

1. Proportions can be used to estimate population parameters from sample data.
2. They are often expressed in terms like $p$ for population proportion and $\hat{p}$ for sample proportion.
3. The formula for calculating a sample proportion is $\hat{p} = \frac{x}{n}$, where $x$ is the number of successes and $n$ is the sample size.
4. Confidence intervals can be constructed around proportions to estimate the true population proportion.
5. Hypothesis testing involving proportions often uses the Z-test for large samples.

Review Questions

• What is the difference between a sample proportion and a population proportion?
• How do you calculate a sample proportion?
• What statistical test would you use to compare two proportions?

Related terms

Ratio: A comparison of two quantities by division.

Percentage: A proportion multiplied by 100 to convert it into a value out of 100.

Confidence Interval: An estimated range of values which is likely to include an unknown population parameter.