stats homework

ECON 2110

Dr. Martin Gritsch

Assignment 5

A reminder about Academic Integrity from the syllabus:

Violations of the Academic Integrity Policy (http://www.wpunj.edu/dotAsset/230122.pdf) will not be tolerated. I am available to help you with graded assignments (within certain limits, e.g., I cannot tell you whether an answer is correct before you submit an assignment), but you are not allowed to work with anyone else on a graded assignment.

To name a few examples,

- working together with another student on a graded assignment

- sharing your work for a graded assignment with another student

- getting help on a graded assignment from another student

- getting help on a graded assignment from a tutor (in person or online)

- uploading a graded assignment to an online tutoring site

- copying another student’s work for a graded assignment

- submitting work for a graded assignment obtained from an online tutoring site

are all violations of the Academic Integrity Policy. The above is not meant to be an exhaustive list of possible violations, so if you have any question about whether something is permissible, I strongly encourage you to check with me ahead of time.

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There are four questions on two pages.

Choose THREE of the FOUR questions (and don’t answer the remaining question)

for a possible total of 18 points.

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Question 1 (6 points)

Chicken Delight claims that at least 90 percent of its orders are delivered within 5 minutes of the time the order was placed. A sample of 100 orders revealed that 84 of them were delivered within 5 minutes. Using a level of significance of 0.05, carry out a hypothesis test for Chicken Delight’s claim.

Question 2 (6 points) As part of the quality control process, a chain of grocery stores carries out a monthly comparison of scanned prices to posted prices. The results of 200 prices are as follows:

	Regular Price Items	Sales Items
Scanned price was too low	9	3
Scanned price was too high	5	13
Scanned price was correct	73	97

Using a significance level of 0.05, carry out a contingency table analysis to test whether there is a relationship between scanning error rates and regular/sales price items.

Question 3 (6 points)

Find an article that was published in 2016 or 2017 that deals with the Consumer Price Index (CPI) and write a summary of at least 100 words. You must provide the article’s URL (or provide the proper citation if it is a print article) in addition to your summary.

Question 4 (6 points)

Part (a) (2 points)

Use the data in “Sales Forecasting.xlsx” to predict the company’s sales for the 2nd quarter of 2017 via a linear trend regression.

Part (b) (2 points)

Use the data in “Sales Forecasting.xlsx” to predict the company’s sales for the 4th quarter of 2020 via a linear trend regression.

Part (c) (2 points)

Which of the two forecasts (in Parts (a) and (b)) is likely to be more accurate? Why?

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