Standard Score for Sample Proportion Calculator
The standard score for the sample proportion is a statistical measure used to compare sample proportions to a known or expected proportion. It’s crucial in hypothesis testing and quality control.
- Enter the sample proportion, sample size, and population size.
- Click ‘Calculate’.
- View the standard score and chart below.
The formula for standard score (z-score) is:
z = (p – P) / √[(P(1 – P) / N) + (p(1 – p) / n)]
where p is the sample proportion, P is the known proportion, N is the population size, and n is the sample size.
| Sample Proportion | Standard Score |
|---|---|
| 0.25 | 0.80 |
| 0.50 | 0.00 |
| 0.75 | -0.80 |
- Always use the correct known proportion (P).
- Ensure your sample size (n) is large enough for accurate results.
- Consider using a confidence interval for more precise estimates.
What is a good standard score?
A standard score between -2 and 2 is typically considered acceptable.
Learn more about statistical methods from the UK’s Office for National Statistics. For a deeper understanding, explore statistics courses on Coursera.