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Suppose we are testing the hypothesis \(H_{0}: p=0.3\) versus \(H_{1}: p>0.3\) and we find the \(P\) -value to be \(0.23 .\) Explain what this means. Would you reject the null hypothesis? Why?

Short Answer

Expert verified
Do not reject the null hypothesis because the P-value of 0.23 is greater than the significance level of 0.05.

Step by step solution

01

Understand the Hypotheses

The null hypothesis (H_0) states that the population proportion ( p) is 0.3 and the alternative hypothesis ( H_1) states that the population proportion ( p) is greater than 0.3.
02

Identify the P-value

The P-value for the test is given as 0.23. The P-value measures the probability of obtaining a test statistic at least as extreme as the one obtained, assuming the null hypothesis is true.
03

Compare the P-value to the Significance Level

Typically, we compare the P-value to a significance level ( alpha ), often set at 0.05. If P-value is less than or equal to alpha , we reject the null hypothesis.
04

Make a Decision

Since 0.23 is greater than 0.05, we do NOT reject the null hypothesis. The P-value is not small enough to provide strong evidence against H_0 .

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

P-value interpretation
The P-value plays a crucial role in hypothesis testing. It indicates the probability of obtaining a test statistic at least as extreme as the one observed, given that the null hypothesis is true. For example, a P-value of 0.23 means there is a 23% chance of observing the given or a more extreme result under the assumption that the null hypothesis holds. A higher P-value, like 0.23, suggests that the observed result is relatively likely when the null hypothesis is true.
null hypothesis
The null hypothesis, usually denoted as H_0, is a statement that there is no effect or no difference. It serves as the starting point for testing. In our example, the null hypothesis is that the population proportion (p) is 0.3. This hypothesis remains 'innocent until proven guilty' and is only rejected if the data provides strong enough evidence against it. We assume H_0 is true when calculating probabilities like the P-value.
significance level
The significance level, denoted by α (alpha), is the threshold that determines when we reject the null hypothesis. Commonly, α is set at 0.05, which corresponds to a 5% risk of rejecting the null hypothesis when it is actually true (Type I error). If the P-value is less than or equal to α, we reject the null hypothesis. For example, if α = 0.05 and the observed P-value is 0.23, we do not reject H_0 because 0.23 > 0.05.
alternative hypothesis
The alternative hypothesis, denoted as H_1, is what you want to support. It usually represents a new effect or difference. In our example, H_1 states that the population proportion (p) is greater than 0.3. While the null hypothesis assumes no change or effect, the alternative hypothesis suggests a specific direction or magnitude of change. If evidence strong enough to reject H_0 is found, we provide support for H_1. However, a high P-value (like 0.23) does not offer such strong evidence, so we do not reject H_0.

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