Listed below are time intervals (min) between eruptions of a geyser. Assume that the "recent" times are within the past few years, the "past" times are from around 20 years ago, and that the two samples are independent simple random sample selected from normally distributed populations. Do not assume that the population standard deviations are equal. Does it appear that the mean time interval has changed? Is the conclusion affected by whether the significance level is 0.10 or 0.01? Recent 79 92 89 79 57 100 63 86 69 89 81 82 56 80 73 103 62 D Past 89 87 93 94 64 86 86 92 88 91 91 91 Let u, be the recent times and let u, be the past times. What are the null and alternative hypotheses? O A. Ho: H= H2 O B. Ho: H H2 H;: H =H2 OC. Ho: H

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**Title: Analyzing Time Intervals Between Geyser Eruptions**

**Introduction:**
The table below displays time intervals (in minutes) between the eruptions of a geyser. The data is divided into "recent" times (collected within the past few years) and "past" times (collected around 20 years ago). Each set consists of simple random samples from populations assumed to be normally distributed. The question is whether the mean time interval has changed, and how the conclusion may be influenced by significance levels of 0.10 and 0.01.

**Data:**
- **Recent Times:** 79, 92, 89, 79, 57, 100, 63, 86, 69, 89, 81, 82, 56, 80, 73, 103, 62
- **Past Times:** 89, 87, 93, 94, 64, 86, 86, 82, 88, 91, 91

**Hypotheses:**
Let \( \mu_1 \) be the mean of the recent times, and \( \mu_2 \) the mean of the past times. Choose the null and alternative hypotheses:

- \( \text{A.} \) 
  - \( H_0: \mu_1 = \mu_2 \) 
  - \( H_1: \mu_1 > \mu_2 \)

- \( \text{B.} \) 
  - \( H_0: \mu_1 \neq \mu_2 \) 
  - \( H_1: \mu_1 = \mu_2 \)

- \( \text{C.} \) 
  - \( H_0: \mu_1 < \mu_2 \) 
  - \( H_1: \mu_1 = \mu_2 \)

- \( \text{D.} \) 
  - \( H_0: \mu_1 = \mu_2 \) 
  - \( H_1: \mu_1 \neq \mu_2 \)

**Calculations:**

1. **Test Statistic:**
   - Calculate the t-value using the formula for independent samples. 
   - \( t = \) [Enter value; Round to two decimal places.]

2.
Transcribed Image Text:**Title: Analyzing Time Intervals Between Geyser Eruptions** **Introduction:** The table below displays time intervals (in minutes) between the eruptions of a geyser. The data is divided into "recent" times (collected within the past few years) and "past" times (collected around 20 years ago). Each set consists of simple random samples from populations assumed to be normally distributed. The question is whether the mean time interval has changed, and how the conclusion may be influenced by significance levels of 0.10 and 0.01. **Data:** - **Recent Times:** 79, 92, 89, 79, 57, 100, 63, 86, 69, 89, 81, 82, 56, 80, 73, 103, 62 - **Past Times:** 89, 87, 93, 94, 64, 86, 86, 82, 88, 91, 91 **Hypotheses:** Let \( \mu_1 \) be the mean of the recent times, and \( \mu_2 \) the mean of the past times. Choose the null and alternative hypotheses: - \( \text{A.} \) - \( H_0: \mu_1 = \mu_2 \) - \( H_1: \mu_1 > \mu_2 \) - \( \text{B.} \) - \( H_0: \mu_1 \neq \mu_2 \) - \( H_1: \mu_1 = \mu_2 \) - \( \text{C.} \) - \( H_0: \mu_1 < \mu_2 \) - \( H_1: \mu_1 = \mu_2 \) - \( \text{D.} \) - \( H_0: \mu_1 = \mu_2 \) - \( H_1: \mu_1 \neq \mu_2 \) **Calculations:** 1. **Test Statistic:** - Calculate the t-value using the formula for independent samples. - \( t = \) [Enter value; Round to two decimal places.] 2.
**Analysis of Geyser Eruption Intervals**

**Context:**
Listed below are time intervals (in minutes) between eruptions of a geyser. The "recent" times are from the past few years, while the "past" times are from approximately 20 years ago. Two independent simple random samples were taken, and it is assumed these samples were independently selected from normally distributed populations. Note that we are not assuming the population standard deviations are equal.

**Objective:**
Determine if there is a statistically significant change in the mean time interval between eruptions over time. Additionally, analyze how the conclusion might be affected by using different significance levels, specifically 0.10 and 0.01.

**Data Sets:**
- **Recent Times (in minutes):** 79, 82, 89, 79, 57, 100, 63, 86, 69, 99, 81, 82, 56, 80, 73, 103, 62
- **Past Times (in minutes):** 89, 87, 93, 94, 64, 86, 92, 88, 98, 81, 91, 91

**Methodology:**
1. **Calculate t-statistic:** The difference in means is evaluated using a t-test for independent samples.
   - Enter t-statistic value: __ (Round to two decimal places as needed.)

2. **Determine P-value:** Compute the P-value for the test.
   - Enter P-value: __ (Round to three decimal places as needed.)

**Hypothesis Testing:**
- **Null Hypothesis (H₀):** Assume no change in the mean time interval between eruptions.
- **Alternatives for Conclusion:**
  - Choose whether to reject or fail to reject H₀ based on the calculated P-value and the significance level (0.10).

**Conclusion Statements:**
- If the P-value is less than the significance level, reject H₀.
- Evaluate if there is sufficient evidence to claim that the mean time interval has changed.

**Significance Level Analysis:**
- Examine if the conclusion varies between significance levels of 0.10 and 0.01. Choose the appropriate response:
  - **A.** The conclusion is not affected; H₀ is not rejected in both cases.
  - **B.** The conclusion is affected; H₀
Transcribed Image Text:**Analysis of Geyser Eruption Intervals** **Context:** Listed below are time intervals (in minutes) between eruptions of a geyser. The "recent" times are from the past few years, while the "past" times are from approximately 20 years ago. Two independent simple random samples were taken, and it is assumed these samples were independently selected from normally distributed populations. Note that we are not assuming the population standard deviations are equal. **Objective:** Determine if there is a statistically significant change in the mean time interval between eruptions over time. Additionally, analyze how the conclusion might be affected by using different significance levels, specifically 0.10 and 0.01. **Data Sets:** - **Recent Times (in minutes):** 79, 82, 89, 79, 57, 100, 63, 86, 69, 99, 81, 82, 56, 80, 73, 103, 62 - **Past Times (in minutes):** 89, 87, 93, 94, 64, 86, 92, 88, 98, 81, 91, 91 **Methodology:** 1. **Calculate t-statistic:** The difference in means is evaluated using a t-test for independent samples. - Enter t-statistic value: __ (Round to two decimal places as needed.) 2. **Determine P-value:** Compute the P-value for the test. - Enter P-value: __ (Round to three decimal places as needed.) **Hypothesis Testing:** - **Null Hypothesis (H₀):** Assume no change in the mean time interval between eruptions. - **Alternatives for Conclusion:** - Choose whether to reject or fail to reject H₀ based on the calculated P-value and the significance level (0.10). **Conclusion Statements:** - If the P-value is less than the significance level, reject H₀. - Evaluate if there is sufficient evidence to claim that the mean time interval has changed. **Significance Level Analysis:** - Examine if the conclusion varies between significance levels of 0.10 and 0.01. Choose the appropriate response: - **A.** The conclusion is not affected; H₀ is not rejected in both cases. - **B.** The conclusion is affected; H₀
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