Questions: The National Institute of Mental Health published an article stating that in any one-year period, approximately 27 percent of American adults suffer from depression or a depressive illness.
In a survey of 100 people in a certain town, the percentage of people suffering from depression or a depressive illness was actually different than 27 percent. The sample proportion was 28%.
a. Choose the correct null and alternative hypothesis.
Ho: p=0.27 and Ha: p ≠ 0.27
Ho: p ≥ 0.28 and Ha: p=0.28
Ho: p ≥ 0.28 and Ha: p<0.28
Ho: p=0.28 and Ha: p>0.28
Ho: p=0.27 and Ha: p<0.27
Ho: p=0.28 and Ha: p<0.28
Ho: p=0.27 and Ha: p>0.27
Transcript text: The National Institute of Mental Health published an article stating that in any one-year period, approximately 27 percent of American adults suffer from depression or a depressive illness.
In a survey of 100 people in a certain town, the percentage of people suffering from depression or a depressive illness was actually different than 27 percentage. The sample proportion was $28 \%$.
a. Choose the correct null and alternative hypothesis.
$H_{o}: p=0.27$ and $H_{a}: p \neq 0.27$
$H_{o}: p \geq 0.28$ and $H_{a}: p=0.28$
$H_{o}: p \geq 0.28$ and $H_{a}: p<0.28$
$H_{o}: p=0.28$ and $H_{a}: p>0.28$
$H_{o}: p=0.27$ and $H_{a}: p<0.27$
$H_{o}: p=0.28$ and $H_{a}: p<0.28$
$H_{o}: p=0.27$ and $H_{a}: p>0.27$
Solution
Solution Steps
Step 1: Hypotheses Formulation
We set up the null and alternative hypotheses as follows:
Null Hypothesis (\(H_0\)): \(p = 0.27\)
Alternative Hypothesis (\(H_a\)): \(p \neq 0.27\)
Step 2: Test Statistic Calculation
The test statistic \(Z\) is calculated using the formula:
\[
Z = \frac{\hat{p} - p_0}{\sqrt{\frac{p_0(1 - p_0)}{n}}}
\]
Substituting the values:
\(\hat{p} = 0.28\)
\(p_0 = 0.27\)
\(n = 100\)
We find:
\[
Z = 0.2252
\]
Step 3: P-value Calculation
The P-value associated with the test statistic is calculated to be:
\[
\text{P-value} = 0.8218
\]
Step 4: Critical Region Determination
For a two-tailed test at a significance level of \(\alpha = 0.05\), the critical region is defined as:
\[
Z < -1.96 \quad \text{or} \quad Z > 1.96
\]
Step 5: Conclusion
Since the calculated test statistic \(Z = 0.2252\) does not fall into the critical region and the P-value \(0.8218\) is greater than \(\alpha = 0.05\), we fail to reject the null hypothesis.
Final Answer
The answer is:
\[
\boxed{H_0: p = 0.27 \text{ is not rejected}}
\]