What is the relationship between confidence intervals and hypothesis testing?

When testing [tex]\( H_0: \mu = \mu_0 \)[/tex] versus [tex]\( H_1: \mu \neq \mu_0 \)[/tex], if a 99% confidence interval does not contain [tex]\( \mu_0 \)[/tex], we (Choose one) reject [tex]\( H_0 \)[/tex] at the 1% level.



Answer :

To understand the relationship between confidence intervals and hypothesis testing, let's delve into both concepts.

### Confidence Intervals:

A confidence interval gives an estimated range of values which is likely to include an unknown population parameter. This range is calculated from a given set of sample data. For example, a 99% confidence interval means that we can be 99% certain that the interval contains the true population parameter.

### Hypothesis Testing:

Hypothesis testing is a statistical method used to make decisions about the population parameters based on sample data.

- Null Hypothesis (H₀): This is the hypothesis that there is no effect or no difference, and it is what we seek to test against.
- Alternative Hypothesis (H₁): This is the hypothesis that there is an effect or a difference.

In the context of this question, the hypotheses are:
- \( H_0: \mu = \mu_0 \)
- \( H_1: \mu \neq \mu_0 \)

### Relationship:

When we calculate a 99% confidence interval for the population mean (μ), this interval provides us with a range of values which we believe, with 99% confidence, includes the true mean. This interval can also be used in hypothesis testing.

1. 99% Confidence Interval and Hypothesis Testing:

If a 99% confidence interval for μ does not contain μ₀, we have significant evidence to reject the null hypothesis \( H_0 \) at the 1% significance level.

2. 99% Confidence Interval and Decision Making:

- If μ₀ is within the 99% confidence interval, we do not reject the null hypothesis \( H_0 \).
- If μ₀ is not within the 99% confidence interval, we reject the null hypothesis \( H_0 \) at the 1% level of significance.

### Specific Answer to the Question:

When testing [tex]\( H_0: \mu = \mu_0 \)[/tex] versus [tex]\( H_1: \mu \neq \mu_0 \)[/tex], if a 99% confidence interval does not contain [tex]\( \mu_0 \)[/tex], we reject [tex]\( H_0 \)[/tex] at the 1% level.