A used car dealer says that the mean price of a three-year-old sports utility vehicle is $19,000. You suspect this claim is incorrect and find that a random sample of 25 similar vehicles has a mean price of $19,648 and a standard deviation of $1915. Is there enough evidence to reject the claim at a = 0.10? Complete parts (a) through (e) below. Assume the population is normally distributed.

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**Hypothesis Testing Example: Used Car Dealer's Claim**

**Scenario:**
A used car dealer states that the mean price of a three-year-old sports utility vehicle (SUV) is $19,000. There is suspicion regarding the validity of this claim. A random sample of 25 similar vehicles shows a mean price of $19,648 with a standard deviation of $1915. The goal is to determine if there is enough evidence to reject the dealer’s claim at a significance level of \(\alpha = 0.10\). The assumption is that the population is normally distributed.

**Steps to Follow:**

(a) **Determine the Rejection Region(s):**

You need to select the correct rejection region(s) and fill in the answer box(es) within your choice. This should be done by rounding to three decimal places as needed.

Options:
- A.  \( \square < t < \square \)
- B.  \( t > \square \)
- C.  \( t < \square \) and \( t > \square \)
- D.  \( t < \square \)

(b) **Find the Standardized Test Statistic \(t\):**

The formula for the standardized test statistic \(t\) is:
\[ t = \frac{\bar{X} - \mu}{s / \sqrt{n}} \]

Where,
- \(\bar{X} = 19,648\) (sample mean)
- \(\mu = 19,000\) (population mean)
- \(s = 1915\) (sample standard deviation)
- \(n = 25\) (sample size)

You need to round the calculated \(t\)-value to two decimal places as needed.

(c) **Decide whether to reject or fail to reject the null hypothesis \(H_{0}\):**

Options:
- A. Reject \( H_0 \) because the test statistic is not in the rejection region(s).
- B. Fail to reject \( H_0 \) because the test statistic is in the rejection region(s).

Click to select your answer(s).

---

**Graphical or Diagram Explanation (if present):**

No graphs or diagrams are provided in the image. The explanation involves understanding hypothesis testing steps and the decision-making process upon obtaining the \( t \)-test results.

This process is important for evaluating claims statistically to make informed decisions based on sample data.
Transcribed Image Text:**Hypothesis Testing Example: Used Car Dealer's Claim** **Scenario:** A used car dealer states that the mean price of a three-year-old sports utility vehicle (SUV) is $19,000. There is suspicion regarding the validity of this claim. A random sample of 25 similar vehicles shows a mean price of $19,648 with a standard deviation of $1915. The goal is to determine if there is enough evidence to reject the dealer’s claim at a significance level of \(\alpha = 0.10\). The assumption is that the population is normally distributed. **Steps to Follow:** (a) **Determine the Rejection Region(s):** You need to select the correct rejection region(s) and fill in the answer box(es) within your choice. This should be done by rounding to three decimal places as needed. Options: - A. \( \square < t < \square \) - B. \( t > \square \) - C. \( t < \square \) and \( t > \square \) - D. \( t < \square \) (b) **Find the Standardized Test Statistic \(t\):** The formula for the standardized test statistic \(t\) is: \[ t = \frac{\bar{X} - \mu}{s / \sqrt{n}} \] Where, - \(\bar{X} = 19,648\) (sample mean) - \(\mu = 19,000\) (population mean) - \(s = 1915\) (sample standard deviation) - \(n = 25\) (sample size) You need to round the calculated \(t\)-value to two decimal places as needed. (c) **Decide whether to reject or fail to reject the null hypothesis \(H_{0}\):** Options: - A. Reject \( H_0 \) because the test statistic is not in the rejection region(s). - B. Fail to reject \( H_0 \) because the test statistic is in the rejection region(s). Click to select your answer(s). --- **Graphical or Diagram Explanation (if present):** No graphs or diagrams are provided in the image. The explanation involves understanding hypothesis testing steps and the decision-making process upon obtaining the \( t \)-test results. This process is important for evaluating claims statistically to make informed decisions based on sample data.
### Hypothesis Testing Example

A used car dealer claims that the mean price of a three-year-old sports utility vehicle (SUV) is $19,000. You suspect this claim is incorrect and find that a random sample of 25 similar vehicles has a mean price of $19,648 and a standard deviation of $1915. Is there enough evidence to reject the claim at a 0.10 significance level? Complete parts (a) through (e) below. Assume the population is normally distributed.

#### (a) Write the claim mathematically and identify \( H_0 \) and \( H_a \).

*Which of the following correctly states \( H_0 \) and \( H_a \)?*

- **A.** 
  - \( H_0: \mu = \$19,000 \)
  - \( H_a: \mu \neq \$19,000 \)
  
- **B.** 
  - \( H_0: \mu \neq \$19,000 \)
  - \( H_a: \mu = \$19,000 \)
  
- **C.** 
  - \( H_0: \mu \geq \$19,000 \)
  - \( H_a: \mu < \$19,000 \)
  
- **D.** 
  - \( H_0: \mu = \$19,000 \)
  - \( H_a: \mu > \$19,000 \)
  
- **E.** 
  - \( H_0: \mu > \$19,000 \)
  - \( H_a: \mu \leq \$19,000 \)
  
- **F.** 
  - \( H_0: \mu = \$19,000 \)
  - \( H_a: \mu < \$19,000 \)

#### (b) Find the critical value(s) and identify the rejection region(s).

*What is/are the critical value(s), \( t_0 \)?*

- \( t_0 = \) ______

*Use a comma to separate answers as needed. Round to three decimal places as needed.*
Transcribed Image Text:### Hypothesis Testing Example A used car dealer claims that the mean price of a three-year-old sports utility vehicle (SUV) is $19,000. You suspect this claim is incorrect and find that a random sample of 25 similar vehicles has a mean price of $19,648 and a standard deviation of $1915. Is there enough evidence to reject the claim at a 0.10 significance level? Complete parts (a) through (e) below. Assume the population is normally distributed. #### (a) Write the claim mathematically and identify \( H_0 \) and \( H_a \). *Which of the following correctly states \( H_0 \) and \( H_a \)?* - **A.** - \( H_0: \mu = \$19,000 \) - \( H_a: \mu \neq \$19,000 \) - **B.** - \( H_0: \mu \neq \$19,000 \) - \( H_a: \mu = \$19,000 \) - **C.** - \( H_0: \mu \geq \$19,000 \) - \( H_a: \mu < \$19,000 \) - **D.** - \( H_0: \mu = \$19,000 \) - \( H_a: \mu > \$19,000 \) - **E.** - \( H_0: \mu > \$19,000 \) - \( H_a: \mu \leq \$19,000 \) - **F.** - \( H_0: \mu = \$19,000 \) - \( H_a: \mu < \$19,000 \) #### (b) Find the critical value(s) and identify the rejection region(s). *What is/are the critical value(s), \( t_0 \)?* - \( t_0 = \) ______ *Use a comma to separate answers as needed. Round to three decimal places as needed.*
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