Over the years, the mean customer satisfaction rating at a local restaurant has been 92. The restaurant was recently remodeled, and now the management claims the mean customer rating, μ, is not equal to 92. In a sample of 68 customers chosen at random, the mean customer rating is 88.2. Assume that the population standard deviation of customer ratings is 14.3. Is there enough evidence to support the claim that the mean customer rating is different from 92? Perform a hypothesis test, using the 0.05 level of significance. (a) State the null hypothesis Ho and the alternative hypothesis H₁. Ho: H₁:0 (b) Perform a Z-test and find the p-value. Here is some information to help you with your Z-test. • The value of the test stati Standard Normal Distribution Step 1: Select one-tailed or two-tailed. O One-tailed O Two-tailed Step 2: Enter the test statistic. (Round to 3 decimal places.) Step 3: Shade the area represented by the p-value. given by Step 4: Enter the p-value. (Round to 3 decimal places.) x-μ 0 μ □<口 020 X • The p-value is two times the area under the curve to the left of the value of the test statistic. X OSO 0=0 ☐#0 0.3+ O>O 0.2+ 0.1+ x (c) Based on your answer to part (b), choose what can be concluded, at the 0.05 level of significance, about the claim made by the management. O Since the p-value is less than (or equal to) the level of significance, the null hypothesis is rejected. So, there is enough evidence to support the claim that the mean customer rating is not equal to 92. O Since the p-value is less than (or equal to) the level of significance, the null hypothesis is not rejected. So, there is not enough evidence to support the claim that the mean customer rating is not equal to 92. O Since the p-value is greater than the level of significance, the null hypothesis is rejected. So, there is enough evidence to support the claim that the mean customer rating is not equal to 92. O Since the p-value is greater than the level of significance, the null hypothesis is not rejected. So, there is not enough evidence to support the claim that the mean customer rating is not equal to 92.

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
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Chapter1: Starting With Matlab
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Over the years, the mean customer satisfaction rating at a local restaurant has been 92. The restaurant was recently remodeled, and now the management claims the mean customer rating, \( \mu \), is not equal to 92. In a sample of 68 customers chosen at random, the mean customer rating is 88.2. Assume that the population standard deviation of customer ratings is 14.3.

Is there enough evidence to support the claim that the mean customer rating is different from 92? Perform a hypothesis test, using the 0.05 level of significance.

### (a) State the null hypothesis \( H_0 \) and the alternative hypothesis \( H_1 \).

- **\( H_0 \)**: \( \mu = 92 \)
- **\( H_1 \)**: \( \mu \neq 92 \)

### (b) Perform a Z-test and find the p-value.

Here is some information to help you with your Z-test.

- The value of the test statistic is given by: 

\[
\frac{\bar{x} - \mu}{\sigma / \sqrt{n}}
\]

- The p-value is two times the area under the curve to the left of the value of the test statistic.

### Diagram Explanation

The diagram shows a standard normal distribution curve with steps to find the p-value:
1. Select one-tailed or two-tailed.
2. Enter the test statistic (round to 3 decimal places).
3. Shade the area represented by the p-value.
4. Enter the p-value (round to 3 decimal places).

### (c) Based on your answer to part (b), choose what can be concluded, at the 0.05 level of significance, about the claim made by the management.

- If the p-value is less than (or equal to) the level of significance, the null hypothesis is rejected. There is enough evidence to support the claim that the mean customer rating is not equal to 92.
- If the p-value is greater than the level of significance, the null hypothesis is not rejected. There is not enough evidence to support the claim that the mean customer rating is not equal to 92. 

Please choose the correct conclusion based on your calculated p-value.
Transcribed Image Text:Over the years, the mean customer satisfaction rating at a local restaurant has been 92. The restaurant was recently remodeled, and now the management claims the mean customer rating, \( \mu \), is not equal to 92. In a sample of 68 customers chosen at random, the mean customer rating is 88.2. Assume that the population standard deviation of customer ratings is 14.3. Is there enough evidence to support the claim that the mean customer rating is different from 92? Perform a hypothesis test, using the 0.05 level of significance. ### (a) State the null hypothesis \( H_0 \) and the alternative hypothesis \( H_1 \). - **\( H_0 \)**: \( \mu = 92 \) - **\( H_1 \)**: \( \mu \neq 92 \) ### (b) Perform a Z-test and find the p-value. Here is some information to help you with your Z-test. - The value of the test statistic is given by: \[ \frac{\bar{x} - \mu}{\sigma / \sqrt{n}} \] - The p-value is two times the area under the curve to the left of the value of the test statistic. ### Diagram Explanation The diagram shows a standard normal distribution curve with steps to find the p-value: 1. Select one-tailed or two-tailed. 2. Enter the test statistic (round to 3 decimal places). 3. Shade the area represented by the p-value. 4. Enter the p-value (round to 3 decimal places). ### (c) Based on your answer to part (b), choose what can be concluded, at the 0.05 level of significance, about the claim made by the management. - If the p-value is less than (or equal to) the level of significance, the null hypothesis is rejected. There is enough evidence to support the claim that the mean customer rating is not equal to 92. - If the p-value is greater than the level of significance, the null hypothesis is not rejected. There is not enough evidence to support the claim that the mean customer rating is not equal to 92. Please choose the correct conclusion based on your calculated p-value.
According to a report done by S & J Power, the mean lifetime of the light bulbs it manufactures is 42 months. A researcher for a consumer advocate group tests this by selecting 32 bulbs at random. For the bulbs in the sample, the mean lifetime is 41 months. It is known that the population standard deviation of the lifetimes is 8 months. Assume that the population is normally distributed. Can we conclude, at the 0.10 level of significance, that the population mean lifetime, μ, of light bulbs made by this manufacturer differs from 42 months?

Perform a two-tailed test. Then complete the parts below.

Carry your intermediate computations to three or more decimal places, and round your responses as specified below. (If necessary, consult a list of formulas.)

(a) State the null hypothesis \( H_0 \) and the alternative hypothesis \( H_1 \).

\[ H_0 : \mu = 42 \]

\[ H_1 : \mu \neq 42 \]

(b) Determine the type of test statistic to use.

[Dropdown: Z]

(c) Find the value of the test statistic. (Round to three or more decimal places.)

[Input box for calculation]

(d) Find the two critical values. (Round to three or more decimal places.)

\[ -1.645 \text{ and } 1.645 \]

(e) Can we conclude that the population mean lifetime of light bulbs made by this manufacturer differs from 42 months?

[Option buttons: Yes No (selected)]
Transcribed Image Text:According to a report done by S & J Power, the mean lifetime of the light bulbs it manufactures is 42 months. A researcher for a consumer advocate group tests this by selecting 32 bulbs at random. For the bulbs in the sample, the mean lifetime is 41 months. It is known that the population standard deviation of the lifetimes is 8 months. Assume that the population is normally distributed. Can we conclude, at the 0.10 level of significance, that the population mean lifetime, μ, of light bulbs made by this manufacturer differs from 42 months? Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places, and round your responses as specified below. (If necessary, consult a list of formulas.) (a) State the null hypothesis \( H_0 \) and the alternative hypothesis \( H_1 \). \[ H_0 : \mu = 42 \] \[ H_1 : \mu \neq 42 \] (b) Determine the type of test statistic to use. [Dropdown: Z] (c) Find the value of the test statistic. (Round to three or more decimal places.) [Input box for calculation] (d) Find the two critical values. (Round to three or more decimal places.) \[ -1.645 \text{ and } 1.645 \] (e) Can we conclude that the population mean lifetime of light bulbs made by this manufacturer differs from 42 months? [Option buttons: Yes No (selected)]
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