If a particular batch of data is approximately normally distributed

If a particular batch of data is approximately normally distributed, we would find that approximately

		2 of every 3 observations would fall between +/- 1 standard deviation around the mean.
		4 of every 5 observations would fall between +/- 1.28 standard deviations around the mean.
		19 of every 20 observations would fall between +/- 2 standard deviations around the mean.
		All the above.

Question 6

Suppose a 98% confidence interval for ? turns out to be (1000, 2100). If this interval was based on a sample of size n=25 explain what assumptions are necessary for this interval to be valid.

		The sampling distribution of the sample mean must have a normal distribution.
		The population must have an approximately normal distribution.
		The sampling distribution must be biased with 24 degrees of freedom.
		The population of salaries must have an approximate t distribution.

Question 7

The mean age of professors at a university is over 55.3 years. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis?

		There is sufficient evidence to reject the claim ? > 55.3.
		There is not sufficient evidence to reject the claim ? > 55.3.
		There is sufficient evidence to support the claim ? > 55.3.
		There is not sufficient evidence to support the claim ? > 55.3 Question 8 Suppose a 95% confidence interval for ? turns out to be ( 100, 230). To make more useful inferences from the data, it is desired to reduce the width of the confidence interval. Which of the following will result in a reduced interval width? Increase the sample size and decrease the confidence level. Decrease the confidence level. Increase the sample size. Question 10 1. The level of significance, ?, is the probability of making a Correct decision Type I error Type II error Type ? error All of these. .

Question 11

1. The ___________the R², and the __________ the standard error, the stronger the relationship between the dependent variable and the independent variable.

		Higher, higher
		Higher, lower
		Lower, higher
		Lower, lower

5 points

Question 12

1. The intercept (b₀) represents

		the estimated average change in Y per unit change in X.
		the predicted value of Y.
		variation around the line of regression.
		predicted value of Y when X = 0.

5 points

Question 13

1. The results of a survey about a recent judicial appointment are given in the table below. Describe, in detail, what a relative frequency histogram would look like. What are the labels on each axis? What are the values on the y-axis?

Response	Frequency
Strongly Favor	30
Favor	15
Neutral	38
Oppose	13
Strongly Oppose	104

2.

Question 14

1. Find the standard deviation of the following sample:

15

16

17

18

19

		2.00
		1.41
		1.58
		1.50

15 points

Question 15

1. Find P( -1.26 ? Z ? 0.47 )

		0.5318
		0.5770
		0.4682
		0.4230

5 points

Question 16

1. Find P( Z ? 3.02)

		0.4987
		0.9788
		0.9987
		0.0013

5 points

Question 17

1. Find z_.20.

		0.42
		-1.28
		0.84
		0.25

5 points

Question 18

1. You are offered a choice where you can take a certain amount of $ 20 or partake in a gamble, where you put up $30 and have a 50% chance of winning $50 and 50% chance of winning $10. The decision tree is drawn for you. What is the expected value at node 2?

Press Tab to enter the content editor. For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac). Content Editor Use arrow keys to select functions Bold Italic Underline — Font family —Andale MonoArialArial BlackBook AntiquaComic Sans MSCourier NewGeorgiaHelveticaImpactSymbolTahomaTerminalTimes New RomanTrebuchet MSVerdanaWebdingsWingdingsFont family — Font size —1 (8pt)2 (10pt)3 (12pt)4 (14pt)5 (18pt)6 (24pt)7 (36pt)Font size Text Color ? Bullet List ? Number List ? Toggle Spell Checker ? Insert/Edit Link Remove Link Bold Italic Underline Strikethrough — Format —HeadingSub Heading 1Sub Heading 2ParagraphFormatted CodeFormat — Font family —Font family — Font size —Font size Bullet List Number List Text Color ? Highlight ? Remove Formatting Cut Copy Paste Find Undo Redo Align Left Align Center Align Right Align Full Indent Outdent Superscript Subscript Insert/Edit Link Remove Link Direction Left to Right Direction Right to Left Line Horizontal Rule Insert Nonbreaking Space Character Toggle Spell Checker Launch Math Editor Insert Mashup ? Show Nonprinting Characters Blockquote Symbol Emotions Anchor Insert/Edit Table Table Row Properties Table Cell Properties Insert Row Before Insert Row After Delete Row Insert Column Before Insert Column After Delete Column Merge Table Cells Split Merged Table Cells HTML Code View Edit CSS Style Preview Help Full Screen Show More Path: Words:0

Question 19

1. You are offered a choice where you can take a certain amount of $ 20 or partake in a gamble, where you put up $30 and have a 50% chance of winning $50 and 50% chance of winning $10. The decision tree is drawn for you. What should you do–take the $20 or gamble?

Press Tab to enter the content editor. For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac). Content Editor Use arrow keys to select functions Bold Italic Underline — Font family —Andale MonoArialArial BlackBook AntiquaComic Sans MSCourier NewGeorgiaHelveticaImpactSymbolTahomaTerminalTimes New RomanTrebuchet MSVerdanaWebdingsWingdingsFont family — Font size —1 (8pt)2 (10pt)3 (12pt)4 (14pt)5 (18pt)6 (24pt)7 (36pt)Font size Text Color ? Bullet List ? Number List ? Toggle Spell Checker ? Insert/Edit Link Remove Link Bold Italic Underline Strikethrough — Format —HeadingSub Heading 1Sub Heading 2ParagraphFormatted CodeFormat — Font family —Font family — Font size —Font size Bullet List Number List Text Color ? Highlight ? Remove Formatting Cut Copy Paste Find Undo Redo Align Left Align Center Align Right Align Full Indent Outdent Superscript Subscript Insert/Edit Link Remove Link Direction Left to Right Direction Right to Left Line Horizontal Rule Insert Nonbreaking Space Character Toggle Spell Checker Launch Math Editor Insert Mashup ? Show Nonprinting Characters Blockquote Symbol Emotions Anchor Insert/Edit Table Table Row Properties Table Cell Properties Insert Row Before Insert Row After Delete Row Insert Column Before Insert Column After Delete Column Merge Table Cells Split Merged Table Cells HTML Code View Edit CSS Style Preview Help Full Screen Show More Path: Words:0

Question 20

1. You are offered a choice where you can take a certain amount of $ 20 or partake in a gamble, where you put up $30 and have a 50% chance of winning $50 and 50% chance of winning $10. The decision tree is drawn for you. How much should you expect to make?

Press Tab to enter the content editor. For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac). Content Editor Use arrow keys to select functions Bold Italic Underline — Font family —Andale MonoArialArial BlackBook AntiquaComic Sans MSCourier NewGeorgiaHelveticaImpactSymbolTahomaTerminalTimes New RomanTrebuchet MSVerdanaWebdingsWingdingsFont family — Font size —1 (8pt)2 (10pt)3 (12pt)4 (14pt)5 (18pt)6 (24pt)7 (36pt)Font size Text Color ? Bullet List ? Number List ? Toggle Spell Checker ? Insert/Edit Link Remove Link Bold Italic Underline Strikethrough — Format —HeadingSub Heading 1Sub Heading 2ParagraphFormatted CodeFormat — Font family —Font family — Font size —Font size Bullet List Number List Text Color ? Highlight ? Remove Formatting Cut Copy Paste Find Undo Redo Align Left Align Center Align Right Align Full Indent Outdent Superscript Subscript Insert/Edit Link Remove Link Direction Left to Right Direction Right to Left Line Horizontal Rule Insert Nonbreaking Space Character Toggle Spell Checker Launch Math Editor Insert Mashup ? Show Nonprinting Characters Blockquote Symbol Emotions Anchor Insert/Edit Table Table Row Properties Table Cell Properties Insert Row Before Insert Row After Delete Row Insert Column Before Insert Column After Delete Column Merge Table Cells Split Merged Table Cells HTML Code View Edit CSS Style Preview Help Full Screen Show More Path: Words:0

Question 21

1. A researcher wants to estimate the average price of television sets sold at Wal-Mart. It is assumed from previous studies that ? = 45. To estimate the average price within $10 with 95% confidence, what sample size should be used?

All that is needed is the answer. However, if you would like the possibility of partial credit, show me your work. (Don’t worry about formatting or symbols.)

Question 22

1. Customers at Ingles have a choice when paying for their groceries. They may check out and pay using the standard cashier assisted checkout, or they may use a new U-Scan procedure. In the standard procedure an Ingles employee scans each item and another employee puts it in a bag and then into the grocery cart. In the U-Scan procedure the customer scans each item, bags it, and places the bags in the cart themselves. The U-Scan procedure is designed to reduce the time a customer spends in the check out line. The store manger wants to know if the mean checkout time using the standard checkout method is longer than using the U-Scan. She gathered the following sample information. The time is measured from when the customer enters the line until their bags are in the cart. Hence the time includes both waiting in line and checking out.

Mean (minutes) Standard deviation (minutes) Sample Size

Standard 5.5 0.4 50

U-Scan 5.3 0.3 100

What are the null and alternative hypotheses that management would be testing? (Don’t worry about formatting your answer.)

Question 23

1. Customers at Ingles have a choice when paying for their groceries. They may check out and pay using the standard cashier assisted checkout, or they may use a new U-Scan procedure. In the standard procedure an Ingles employee scans each item and another employee puts it in a bag and then into the grocery cart. In the U-Scan procedure the customer scans each item, bags it, and places the bags in the cart themselves. The U-Scan procedure is designed to reduce the time a customer spends in the check out line. The store manger wants to know if the mean checkout time using the standard checkout method is longer than using the U-Scan. She gathered the following sample information. The time is measured from when the customer enters the line until their bags are in the cart. Hence the time includes both waiting in line and checking out.

Mean (minutes) Standard deviation (minutes) Sample Size

Standard 5.5 0.4 50

U-Scan 5.3 0.3 100

If ? = .05 and if the Excel output shows that p-value = 0.0013, would you reject Ho? Why or why not?

Question 24

1. Customers at Ingles have a choice when paying for their groceries. They may check out and pay using the standard cashier assisted checkout, or they may use a new U-Scan procedure. In the standard procedure an Ingles employee scans each item and another employee puts it in a bag and then into the grocery cart. In the U-Scan procedure the customer scans each item, bags it, and places the bags in the cart themselves. The U-Scan procedure is designed to reduce the time a customer spends in the check out line. The store manger wants to know if the mean checkout time using the standard checkout method is longer than using the U-Scan. She gathered the following sample information. The time is measured from when the customer enters the line until their bags are in the cart. Hence the time includes both waiting in line and checking out.

Mean (minutes) Standard deviation (minutes) Sample Size

Standard 5.5 0.4 50

U-Scan 5.3 0.3 100

Can we conclude that the U-Scan system is better than the standard checkout?

Question 25

1. The following data represent the age of batteries (in hours) for a random sample of 10 full charges on a fifth generation iPod music player:

7.3

10.2

12.9

10.8

12.1

6.6

10.2

9

8.5

7.1

2.
The following Excel output was obtained. What is the point estimate of the population mean?

3.

hours
Mean	9.47
Standard Error	0.676929
Median	9.6
Mode	10.2
Standard Deviation	2.140639
Sample Variance	4.582333
Kurtosis	-1.09156
Skewness	0.190992
Range	6.3
Minimum	6.6
Maximum	12.9
Sum	94.7
Count	10
Confidence Level(95.0%) Question 26 1. The following data represent the age of batteries (in hours) for a random sample of 10 full charges on a fifth generation iPod music player: 7.3 10.2 12.9 10.8 12.1 6.6 10.2 9 8.5 7.1 2. The following Excel output was obtained. Construct a 95% confidence interval for the mean number of hours the batteries will last in the player. 3. hours Mean 9.47 Standard Error 0.676929 Median 9.6 Mode 10.2 Standard Deviation 2.140639 Sample Variance 4.582333 Kurtosis -1.09156 Skewness 0.190992 Range 6.3 Minimum 6.6 Maximum 12.9 Sum 94.7 Count 10 Confidence Level(95.0%) 1.531321 Question 27 1. A sample of scores on an examination given in two different classes is examined. The following Excel output was obtained. Use ? = .05. In order to determine if Class 2 has a different grade from Class 1, what are the null and alternative hypotheses? t-Test: Two-Sample Assuming Unequal Variances class 1 class 2 Mean 78 79 Variance 90 47.333 Observations 9 7 Hypothesized Mean Difference 0 df 14 t Stat -0.244 P(T<=t) one-tail 0.405 t Critical one-tail 1.761 P(T<=t) two-tail 0.811 t Critical two-tail 2.145 Question 28 1. A sample of scores on an examination given in two different classes is examined. The following Excel output was obtained. Use ? = .05. Exactly what p-value did you use to answer to determine if Class 2 has a different average? t-Test: Two-Sample Assuming Unequal Variances class 1 class 2 Mean 78 79 Variance 90 47.333 Observations 9 7 Hypothesized Mean Difference 0 df 14 t Stat -0.244 P(T<=t) one-tail 0.405 t Critical one-tail 1.761 P(T<=t) two-tail 0.811 t Critical two-tail 2.145 2. Press Tab to enter the content editor. For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac). Content Editor Use arrow keys to select functions Bold Italic Underline — Font family —Andale MonoArialArial BlackBook AntiquaComic Sans MSCourier NewGeorgiaHelveticaImpactSymbolTahomaTerminalTimes New RomanTrebuchet MSVerdanaWebdingsWingdingsFont family — Font size —1 (8pt)2 (10pt)3 (12pt)4 (14pt)5 (18pt)6 (24pt)7 (36pt)Font size Text Color ? Question 29 1. A sample of scores on an examination given in two different classes is examined. The following Excel output was obtained. Use ? = .05. Does Class 2 have a different grade? t-Test: Two-Sample Assuming Unequal Variances class 1 class 2 Mean 78 79 Variance 90 47.333 Observations 9 7 Hypothesized Mean Difference 0 df 14 t Stat -0.244 P(T<=t) one-tail 0.405 t Critical one-tail 1.761 P(T<=t) two-tail 0.811 t Critical two-tail 2.145 Question 30 1. Auto, Inc., a fictional automobile manufacturer, is interested in estimating the value derived from a proposed Strategic Alternative (SA). The SA, posed by the CEO of the company, is to acquire an elite, high-end auto company where the average retail price of a car is $80,000. As part of this task, the acquisition team develops a three-year market analysis to determine if adequate market demand exists for luxury automobiles. The team chooses to use the predictive power of regression analysis to help make these projections. The first step in this process is to understand what drives total market demand for elite, high-end luxury automobiles. After analyzing the industry, the group hypothesizes that gross domestic product, or GDP, is a key predictor of market demand for these automobiles. To gather historical GDP data, the team turns to online databases located on the Federal Reserve Board website.To gather data on new vehicle sales for elite, high-end luxury cars, it uses the Bureau of Labor Statistics’ online databases on new vehicle car sales. (The GDP data is in billions of dollars and the sales data is in thousands of units.) Is GDP a valid predictor of sales? How do you know? SUMMARY OUTPUT Regression Statistics Multiple R 0.831453 R Square 0.691314 Adjusted R Square 0.652728 Standard Error 251.102335 Observations 10 ANOVA df SS MS F Significance F Regression 1 1129665.838 1129665.84 17.9163069 0.0028655 Residual 8 504419.0623 63052.3828 Total 9 1634084.9 Coefficients Standard Error t Stat P-value Intercept 739.44976 519.58568 1.42315 0.19250 GDP (in $billions) 0.28527 0.06740 4.23277 0.00287 Question 31 1. Auto, Inc., a fictional automobile manufacturer, is interested in estimating the value derived from a proposed Strategic Alternative (SA). The SA, posed by the CEO of the company, is to acquire an elite, high-end auto company where the average retail price of a car is $80,000. As part of this task, the acquisition team develops a three-year market analysis to determine if adequate market demand exists for luxury automobiles. The team chooses to use the predictive power of regression analysis to help make these projections. The first step in this process is to understand what drives total market demand for elite, high-end luxury automobiles. After analyzing the industry, the group hypothesizes that gross domestic product, or GDP, is a key predictor of market demand for these automobiles. To gather historical GDP data, the team turns to online databases located on the Federal Reserve Board website.To gather data on new vehicle sales for elite, high-end luxury cars, it uses the Bureau of Labor Statistics’ online databases on new vehicle car sales. (The GDP data is in billions of dollars and the sales data is in thousands of units.) If the GDP is at 12,000 billion dollars, how many thousands of units of cars would you expect to be sold? SUMMARY OUTPUT Regression Statistics Multiple R 0.831453 R Square 0.691314 Adjusted R Square 0.652728 Standard Error 251.102335 Observations 10 ANOVA df SS MS F Significance F Regression 1 1129665.838 1129665.84 17.9163069 0.0028655 Residual 8 504419.0623 63052.3828 Total 9 1634084.9 Coefficients Standard Error t Stat P-value Intercept 739.44976 519.58568 1.42315 0.19250 GDP (in $billions) 0.28527 0.06740 4.23277 0.00287 Question 32 1. Auto, Inc., a fictional automobile manufacturer, is interested in estimating the value derived from a proposed Strategic Alternative (SA). The SA, posed by the CEO of the company, is to acquire an elite, high-end auto company where the average retail price of a car is $80,000. As part of this task, the acquisition team develops a three-year market analysis to determine if adequate market demand exists for luxury automobiles. The team chooses to use the predictive power of regression analysis to help make these projections. The first step in this process is to understand what drives total market demand for elite, high-end luxury automobiles. After analyzing the industry, the group hypothesizes that gross domestic product, or GDP, is a key predictor of market demand for these automobiles. To gather historical GDP data, the team turns to online databases located on the Federal Reserve Board website.To gather data on new vehicle sales for elite, high-end luxury cars, it uses the Bureau of Labor Statistics’ online databases on new vehicle car sales. (The GDP data is in billions of dollars and the sales data is in thousands of units.) 1. Interpret b1. SUMMARY OUTPUT Regression Statistics Multiple R 0.831453 R Square 0.691314 Adjusted R Square 0.652728 Standard Error 251.102335 Observations 10 ANOVA df SS MS F Significance F Regression 1 1129665.838 1129665.84 17.9163069 0.0028655 Residual 8 504419.0623 63052.3828 Total 9 1634084.9 Coefficients Standard Error t Stat P-value Intercept 739.44976 519.58568 1.42315 0.19250 GDP (in $billions) 0.28527 0.06740 4.23277 0.00287