A company that develops an automated customer service model is interested in knowing whether two versions, Version A and Version B, will get different ratings from customers. Participants in a focus group are taken through samples from both versions, then take a survey to rate each version. A summary of the data obtained from the study is given below. Assume ratings from the different surveys generally have the same standard deviation. Version A Version B Mean 33.133 28.67 15 15 Observations Pearson Correlation Hypothesized Mean Difference -0.325 0.00 df 14 t Stat -1.426 P(T<=t) one-tail 0.088 P= Ex: 1.234 t Critical one-tail -1.345 P(T<=t) two-tail 0.176 -1.761 t Critical two-tail Confidence Level 95% -3 -2 -1 3 t = Ex: 1.234 n = Ex: 9 Degrees of freedom: df = Point estimate for Version A: 1 = Ex: 1234 Point estimate for Version B: X₂ = 0 1 t=

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### Hypothesis Testing for the Difference Between Two Population Means

#### Scenario
A company that develops an automated customer service model seeks to determine whether two versions, Version A and Version B, will receive different ratings from customers. Participants in a focus group are exposed to samples from both versions, followed by a survey to rate each version. Below is a summary of the data obtained from the study. The study assumes that ratings from the different surveys generally have the same standard deviation.

#### Data Summary

| Statistic                       | Version A | Version B |
|---------------------------------|-----------|-----------|
| Mean                            | 33.133    | 28.67     |
| Observations                    | 15        | 15        |
| Pearson Correlation             | -0.325    | -         |
| Hypothesized Mean Difference    | 0.00      | -         |
| Degrees of Freedom (df)         | 14        | -         |
| t Stat                          | -1.426    | -         |
| P(T≤t) one-tail                 | 0.088     | -         |
| t Critical one-tail             | -1.345    | -         |
| P(T≤t) two-tail                 | 0.176     | -         |
| t Critical two-tail             | -1.761    | -         |
| Confidence Level                | 95%       | -         |

#### Explanation of the Data

- **Mean**: The average rating for Version A is 33.133 and for Version B is 28.67.
- **Observations**: Both versions had 15 participants each.
- **Pearson Correlation**: Correlation between the two ratings is -0.325.
- **Hypothesized Mean Difference**: Assumed to be 0.00 for testing purposes.
- **Degrees of Freedom (df)**: Calculated as 14.
- **t Stat**: The computed t-value for the test statistic is -1.426.
- **P(T≤t) one-tail**: The p-value for a one-tailed test is 0.088.
- **t Critical one-tail**: The critical t-value for a one-tailed test at a 95% confidence level is -1.345.
- **P(T≤t) two-tail**: The p-value for a two-tailed test is 0.176.
- **t Critical two-tail
Transcribed Image Text:### Hypothesis Testing for the Difference Between Two Population Means #### Scenario A company that develops an automated customer service model seeks to determine whether two versions, Version A and Version B, will receive different ratings from customers. Participants in a focus group are exposed to samples from both versions, followed by a survey to rate each version. Below is a summary of the data obtained from the study. The study assumes that ratings from the different surveys generally have the same standard deviation. #### Data Summary | Statistic | Version A | Version B | |---------------------------------|-----------|-----------| | Mean | 33.133 | 28.67 | | Observations | 15 | 15 | | Pearson Correlation | -0.325 | - | | Hypothesized Mean Difference | 0.00 | - | | Degrees of Freedom (df) | 14 | - | | t Stat | -1.426 | - | | P(T≤t) one-tail | 0.088 | - | | t Critical one-tail | -1.345 | - | | P(T≤t) two-tail | 0.176 | - | | t Critical two-tail | -1.761 | - | | Confidence Level | 95% | - | #### Explanation of the Data - **Mean**: The average rating for Version A is 33.133 and for Version B is 28.67. - **Observations**: Both versions had 15 participants each. - **Pearson Correlation**: Correlation between the two ratings is -0.325. - **Hypothesized Mean Difference**: Assumed to be 0.00 for testing purposes. - **Degrees of Freedom (df)**: Calculated as 14. - **t Stat**: The computed t-value for the test statistic is -1.426. - **P(T≤t) one-tail**: The p-value for a one-tailed test is 0.088. - **t Critical one-tail**: The critical t-value for a one-tailed test at a 95% confidence level is -1.345. - **P(T≤t) two-tail**: The p-value for a two-tailed test is 0.176. - **t Critical two-tail
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