Math302 Statistics Quiz

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Question 2 of 17

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An investor wants to compare the risks associated with two different stocks. One way to measure the risk of a given stock is to measure the variation in the stock’s daily price changes.

In an effort to test the claim that the variance in the daily stock price changes for stock 1 is different from the variance in the daily stock price changes for stock 2, the investor obtains a random sample of 21 daily price changes for stock 1 and 21 daily price changes for stock 2.

The summary statistics associated with these samples are: n₁ = 21, s₁ = .725, n₂ = 21, s₂ = .529.

If you compute the test value by placing the larger variance in the numerator, at the .05 level of significance, would you conclude that the risks associated with these two stocks are different?

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Question 3 of 17

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A researcher hypothesizes that the variation in the amount of money spent on business dinners is greater than the variation of the amount of money spent on lunches. The variance of nine business dinners was $6.12 and the variance of 12 business lunches was $0.87. What is the test value?

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Part 2 of 8 -

Question 4 of 17

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In choosing the “best-fitting” line through a set of points in linear regression, we choose the one with the:

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Question 5 of 17

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The standard error of the estimate, s_est, is essentially the

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Question 6 of 17

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In regression analysis, the variable we are trying to explain or predict is called the

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Question 7 of 17

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If an estimated regression line has a Y-intercept of –7.5 and a slope of 2.5, then when X = 3, the actual value of Y is:

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Question 8 of 17

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The marketing manager of a large supermarket chain would like to use shelf space to predict the sales of pet food. For a random sample of 12 similar stores, she gathered the following information regarding the shelf space, in feet, devoted to pet food and the weekly sales in hundreds of dollars. .

Store	1	2	3	4	5	6
Shelf Space	5	5	5	10	10	10
Weekly Sales	1.6	2.2	1.4	1.9	2.4	2.6

Store	7	8	9	10	11	12
Shelf Space	15	15	15	20	20	20
Weekly Sales	2.3	2.7	2.8	2.6	2.9	3.1

Is the correlation between weekly sales and shelf space significant at the .01 level of significance?

Yes, the computed t-test statistic is less than the critical value.

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Part 3 of 8 -

Question 9 of 17

2.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

A field researcher is gathering data on the trunk diameters of mature pine and spruce trees in a certain area. The following are the results of his random sampling. Can he conclude, at the 0.10 level of significance, that the average trunk diameter of a pine tree is greater than the average diameter of a spruce tree?

	Pine trees	Spruce trees
Sample size	25	35
Mean trunk diameter (cm)	55	48
Sample variance	100	140

What is the test value for this hypothesis test?

Test value:

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Part 8 of 8 -

Question 16 of 17

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A simple linear regression equation is given by y' = 5 + 3x. The predicted value of Y when X = 3 is 5.

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Question 17 of 17

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In simple linear regression analysis, the relationship between the response variable Y and the explanatory variable X is a straight line. This means that all data points lie on the line.