# Confidence Intervals for Proportions by David Spade, PhD

The lecture Confidence Intervals for Proportions by David Spade, PhD is from the course Learn Statistics - Become Data Smart. It contains the following chapters:

• Confidence Intervals for Proportions
• Constructing the Interval
• Margin of Error
• Assumptions and Conditions
• Pitfalls to Avoid

### Included Quiz Questions

1. We know that we have constructed an interval that captures the true population proportion.
2. We no longer need to rely on a single value to estimate the population proportion.
3. We are guaranteed a certain probability that the interval captures the true value of the population parameter.
4. We have more confidence in a range than in a single value as an estimate of the population proportion.
5. We are able to adjust confidence and precision to match our needs.
1. We are 95% confident that the true population proportion is between a and b.
2. We know that the true population proportion is between a and b.
3. We know that the true population proportion is p.
4. We are 95% confident that the true standard deviation is between a and b.
5. We are 95% confident that the true population proportion is outside of a and b.
1. A smaller margin of error is associated with a smaller confidence interval.
2. A smaller margin of error is associated with a larger confidence interval.
3. A larger margin of error is associated with a smaller confidence interval.
4. We can change the confidence level using the same sample size without affecting the margin of error.
5. The larger the margin of error, the more confidence we have in a result.
1. We need our sample size to be at least 10% of the population.
2. We need to observe at least 10 successes.
3. We need to observe at least 10 failures.
4. We need our sample to be random.
5. All trials must be independent of each other.
1. The confidence level can be increased while also decreasing the margin of error by increasing the sample size.
2. The interval is based on the sample proportion, so any statements you can make based on the interval should be about the sample proportion.
3. 95% confidence means that you are 95% certain that the population proportion lies in your interval.
4. Values near the center of the interval are more plausible than values near the edges.
5. The confidence level is a fixed, immutable property.
1. 0.4; 0
2. 0.5; 0
3. 0.3; -1
4. 0.2; -1
5. 0.5; -1
1. 0.25
2. 0.5
3. 0
4. 0.3
5. 0.8