## One Proportion Z Interval

**Overview:**

When you have a single proportion based on data from a sample and you want to estimate the true proportion in the population.

**Assumptions and Conditions**

- Randomization Condition- The data is sampled at random or generated from a random environment.
- Success/failure condition – We must expect at least 10 successes and 10 failures. ( np>10 & nq>10)
- 10% condition- If the sample exceeds 10% of the population a normal model may no longer be appropriate.

**Ways to do it**

- Calculator –STAT- TESTS- A: 1-PropZInt- enter number of successes observed and the sample size, specify a confidence level.
- By Hand:

**Conclusion in Context**

“I am ___% confident that __________ is between ___ and ___”