A mail-order company has two warehouses, one on the West Coast and the second on the East Coast. The company's policy is to mail all orders placed with it within 72 hours. The company's quality control department checks quite often whether or not this policy is maintained at the two warehouses. Arecently taken sample of 407 orders placed with the warehouse on the West Coast showed that 366 of them were mailed within 72 hours. Another sample of 297 orders placed with the warehouse on the East Coast showed that 281 of them were mailed within 72 hours. Let p, be the proportion of all orders placed with the warehouse on the West Coast that are mailed within 72 hours, and p, be the proportion of all orders placed with the warehouse on the East Coast that are mailed within 72 hours. a. Construct a 90% confidence interval for the difference between the proportions of all orders placed at the two warehouses that are mailed within 72 hours. Round your answers to two decimal places. to i b. Using a 1% significance level, can you conclude that the proportion of all orders placed at the warehouse on the West Coast that are mailed within 72 hours is lower than the corresponding proportion for the warehouse on the East Coast? We conclude that the proportion of all orders placed at the warehouse on the West Coast that are mailed within 72 hours is lower than the corresponding proportion for the warehouse on the East Coast.

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Chapter1: Starting With Matlab
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A mail-order company has two warehouses, one on the West Coast and the other on the East Coast. The company’s policy is to mail all orders placed with it within 72 hours. The company’s quality control department checks quite often whether or not this policy is maintained at the two warehouses. A recently taken sample of 407 orders placed with the warehouse on the West Coast showed that 366 of them were mailed within 72 hours. Another sample of 297 orders placed with the warehouse on the East Coast showed that 281 of them were mailed within 72 hours.

Let \( p_1 \) be the proportion of all orders placed with the warehouse on the West Coast that are mailed within 72 hours, and \( p_2 \) be the proportion of all orders placed with the warehouse on the East Coast that are mailed within 72 hours.

a. Construct a 90% confidence interval for the difference between the proportions of all orders placed at the two warehouses that are mailed within 72 hours.

Round your answers to two decimal places.

b. Using a 1% significance level, can you conclude that the proportion of all orders placed at the warehouse on the West Coast that are mailed within 72 hours is lower than the corresponding proportion for the warehouse on the East Coast?

We conclude that the proportion of all orders placed at the warehouse on the West Coast that are mailed within 72 hours is [lower/not lower] than the corresponding proportion for the warehouse on the East Coast.

**Note:**
- There is a confidence interval entry field with text boxes for input and dropdown options to conclude the hypothesis test.
- The dropdown options contain two choices:
  - lower
  - not lower
Transcribed Image Text:A mail-order company has two warehouses, one on the West Coast and the other on the East Coast. The company’s policy is to mail all orders placed with it within 72 hours. The company’s quality control department checks quite often whether or not this policy is maintained at the two warehouses. A recently taken sample of 407 orders placed with the warehouse on the West Coast showed that 366 of them were mailed within 72 hours. Another sample of 297 orders placed with the warehouse on the East Coast showed that 281 of them were mailed within 72 hours. Let \( p_1 \) be the proportion of all orders placed with the warehouse on the West Coast that are mailed within 72 hours, and \( p_2 \) be the proportion of all orders placed with the warehouse on the East Coast that are mailed within 72 hours. a. Construct a 90% confidence interval for the difference between the proportions of all orders placed at the two warehouses that are mailed within 72 hours. Round your answers to two decimal places. b. Using a 1% significance level, can you conclude that the proportion of all orders placed at the warehouse on the West Coast that are mailed within 72 hours is lower than the corresponding proportion for the warehouse on the East Coast? We conclude that the proportion of all orders placed at the warehouse on the West Coast that are mailed within 72 hours is [lower/not lower] than the corresponding proportion for the warehouse on the East Coast. **Note:** - There is a confidence interval entry field with text boxes for input and dropdown options to conclude the hypothesis test. - The dropdown options contain two choices: - lower - not lower
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