To test Ho: u= 40 versus H,: u< 40, a random sample of size n= 25 is obtained from a population that is known to be normally distributed. Complete parts (a) through (d) below. E Click here to view the t-Distribution Area in Right Tail. (a) If x= 37.4 and s = 13.6, compute the test statistic. to = - 0.956 (Round three decimal places as needed.) (b) If the researcher decides to test this hypothesis at the a = 0.05 level of significance, determine the critical value(s). Although technology or a t-distribution table can be used to find the critical value, in this problem use the t-distribution table given. Critical Value: (Round to three decimal places. Use a comma to separate answers as needed.)

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To test \( H_0: \mu = 40 \) versus \( H_1: \mu < 40 \), a random sample of size \( n = 25 \) is obtained from a population that is known to be normally distributed. Complete parts (a) through (d) below.

[Table Icon] Click here to view the t-Distribution Area in Right Tail.

**(a)** If \( \bar{x} = 37.4 \) and \( s = 13.6 \), compute the test statistic.

\( t_0 = -0.956 \)  (Round to three decimal places as needed.)

**(b)** If the researcher decides to test this hypothesis at the \( \alpha = 0.05 \) level of significance, determine the critical value(s). Although technology or a t-distribution table can be used to find the critical value, in this problem use the t-distribution table given.

Critical Value: \_\_\_

(Round to three decimal places. Use a comma to separate answers as needed.)
Transcribed Image Text:To test \( H_0: \mu = 40 \) versus \( H_1: \mu < 40 \), a random sample of size \( n = 25 \) is obtained from a population that is known to be normally distributed. Complete parts (a) through (d) below. [Table Icon] Click here to view the t-Distribution Area in Right Tail. **(a)** If \( \bar{x} = 37.4 \) and \( s = 13.6 \), compute the test statistic. \( t_0 = -0.956 \) (Round to three decimal places as needed.) **(b)** If the researcher decides to test this hypothesis at the \( \alpha = 0.05 \) level of significance, determine the critical value(s). Although technology or a t-distribution table can be used to find the critical value, in this problem use the t-distribution table given. Critical Value: \_\_\_ (Round to three decimal places. Use a comma to separate answers as needed.)
The table provided is a t-distribution table, which is used to determine the critical values of the t-distribution for hypothesis testing. This specific table shows the areas in the right tail for various degrees of freedom (df) and significance levels.

### Structure of the Table:

- **Columns:** 
  - The columns represent significance levels (α) which are the probabilities in the right tail of the t-distribution. These levels include: 0.25, 0.20, 0.15, 0.10, 0.05, 0.025, 0.02, 0.01, 0.005, 0.0025, 0.001, 0.0005.
  
- **Rows:**
  - The rows represent the degrees of freedom (df). These range from 1 to 100, and then increase in increments: 120, 150, 200, 300, 500, and 1000.

### How to Use the Table:

1. **Determine the Degrees of Freedom (df):** 
   - In hypothesis testing, the degrees of freedom are typically calculated based on your sample size. For a single sample t-test, df = n - 1, where n is the sample size.

2. **Select the Significance Level (α):** 
   - Choose the column that corresponds to your desired significance level. This level represents the probability of rejecting the null hypothesis when it is actually true (Type I error).

3. **Find the Critical Value:**
   - Locate your degrees of freedom in the far left or right column. Follow across that row to the significance level column to find your critical t-value.

This critical value is used to compare against your calculated t-statistic. If your t-statistic is larger than the critical value, you reject the null hypothesis.

### Example:

- Suppose you are conducting a test with a significance level of 0.05 and have 15 degrees of freedom. Find the row for `df = 15` and the column for `α = 0.05`. The intersection is approximately `2.131`. This is your critical t-value.

This table is essential for achieving accurate results in t-distribution related statistical analysis, and it helps quantify the certainty of your conclusions.
Transcribed Image Text:The table provided is a t-distribution table, which is used to determine the critical values of the t-distribution for hypothesis testing. This specific table shows the areas in the right tail for various degrees of freedom (df) and significance levels. ### Structure of the Table: - **Columns:** - The columns represent significance levels (α) which are the probabilities in the right tail of the t-distribution. These levels include: 0.25, 0.20, 0.15, 0.10, 0.05, 0.025, 0.02, 0.01, 0.005, 0.0025, 0.001, 0.0005. - **Rows:** - The rows represent the degrees of freedom (df). These range from 1 to 100, and then increase in increments: 120, 150, 200, 300, 500, and 1000. ### How to Use the Table: 1. **Determine the Degrees of Freedom (df):** - In hypothesis testing, the degrees of freedom are typically calculated based on your sample size. For a single sample t-test, df = n - 1, where n is the sample size. 2. **Select the Significance Level (α):** - Choose the column that corresponds to your desired significance level. This level represents the probability of rejecting the null hypothesis when it is actually true (Type I error). 3. **Find the Critical Value:** - Locate your degrees of freedom in the far left or right column. Follow across that row to the significance level column to find your critical t-value. This critical value is used to compare against your calculated t-statistic. If your t-statistic is larger than the critical value, you reject the null hypothesis. ### Example: - Suppose you are conducting a test with a significance level of 0.05 and have 15 degrees of freedom. Find the row for `df = 15` and the column for `α = 0.05`. The intersection is approximately `2.131`. This is your critical t-value. This table is essential for achieving accurate results in t-distribution related statistical analysis, and it helps quantify the certainty of your conclusions.
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