# Is a 95% confidence interval wider than a 90% confidence interval?

A 99 percent

**confidence interval**would be**wider than**a**95**percent**confidence interval**(for example, plus or minus 4.5 percent instead of 3.5 percent). A**90**percent**confidence interval**would be narrower (plus or minus 2.5 percent, for example).A.

### What is the effect of increasing the level of confidence on the width of the interval?

**Increasing**the sample size decreases the

**width**of

**confidence intervals**, because it decreases the standard error. c) The statement, "the 95%

**confidence interval**for the population mean is (350, 400)", is equivalent to the statement, "there is a 95% probability that the population mean is between 350 and 400".

#### What is the significance of the width of the confidence interval?

Increasing the sample size decreases the**width**of**confidence intervals**, because it decreases the standard error. c) The statement, "the 95%**confidence interval**for the population**mean**is (350, 400)", is equivalent to the statement, "there is a 95% probability that the population**mean**is between 350 and 400".#### What is the confidence interval in statistics?

In**statistics**, a**confidence interval**(CI) is a type of**interval**estimate, computed from the**statistics**of the observed data, that might contain the true value of an unknown population parameter. Most commonly, the 95%**confidence**level is used.#### What is the margin of error in statistics?

The**margin of error**for a particular**statistic**of interest is usually defined as the radius (or half the width) of the confidence interval for that**statistic**. The term can also be used to mean sampling**error**in general.

B.

### What is a good 95% confidence interval?

If repeated samples were taken and the 95% confidence interval was computed for each sample, 95% of the intervals would contain the population mean. A 95% confidence interval has a

**0.95**probability of containing the population mean. 95% of the population distribution is contained in the confidence interval.#### What is the z score for 99 confidence interval?

Confidence IntervalsDesired Confidence Interval Z Score 90% 95% 99% 1.645 1.96 2.576 #### How do you know if a confidence interval is significant?

**So, if your significance level is 0.05, the corresponding confidence level is 95%.**- If the P value is less than your significance (alpha) level, the hypothesis test is statistically significant.
- If the confidence interval does not contain the null hypothesis value, the results are statistically significant.

#### How can the width of a confidence interval be reduced?

- Increase the sample size. Often, the most practical way to decrease the margin of error is to increase the sample size.
- Reduce variability. The less that your data varies, the more precisely you can estimate a population parameter.
- Use a one-sided confidence interval.
- Lower the confidence level.

C.

### How can the width of a confidence interval be reduced?

- Increase the sample size. Often, the most practical way to decrease the margin of error is to increase the sample size.
- Reduce variability. The less that your data varies, the more precisely you can estimate a population parameter.
- Use a one-sided confidence interval.
- Lower the confidence level.

#### What is the significance of the width of the confidence interval?

Increasing the sample size decreases the**width**of**confidence intervals**, because it decreases the standard error. c) The statement, "the 95%**confidence interval**for the population**mean**is (350, 400)", is equivalent to the statement, "there is a 95% probability that the population**mean**is between 350 and 400".#### What happens to the margin of error if you increase the confidence level?

Answer: As sample size**increases, the margin of error**decreases. As the variability in the population**increases, the margin of error increases**. As the**confidence level increases, the margin of error increases**.#### Why are some confidence intervals wider?

Apparently a narrow**confidence interval**implies that there is a smaller chance of obtaining an observation within that**interval**, therefore, our accuracy is higher. Also a 95%**confidence interval**is narrower than a 99%**confidence interval**which is**wider**. The 99%**confidence interval**is more accurate than the 95%.

Updated: 3rd December 2019