MT1 Practice Packet

Question 1

HW1 Practice Probs

2a

Answer 1

See HW1 Practice Problem Solutions

Question 2

HW1 Lab Problems

4a

Answer 2

See solutions

Question 3

HW1 Practice Probs

6a

Answer 3

See HW1 Practice Problem Solutions

Question 3

Lec 3 PS

1a

Answer 3

See notes

Question 4

HW1 Lab Problems

2a

Answer 4

See solutions

Question 4

Lec 3 PS

1b

Answer 4

See notes

Question 4

HW Series 3: Lab

1b

Answer 4

See key

Question 5

HW1 Lab Problems

3b

Answer 5

See solutions

Question 5

HW1 Practice Probs

1b

Answer 5

See HW1 Practice Problem Solutions

Question 5

HW Series 2: Practice

8b

Answer 5

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Question 5

HW Series 3: Practice

8v

Answer 5

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Question 6

HW Series 2: Lab

5b

Answer 6

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Question 6

HW Series 2: Lab

8a

Answer 6

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Question 7

HW Series 2: Practice

7

Answer 7

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Question 7

HW Series 2: Practice

8a

Answer 7

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Question 7

HW Series 3: Practice

8ii

Answer 7

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Question 8

Lecture 2

You poll 1000 U.S. voters and ask them if they will vote Democrat or Republican in the upcoming national election. Your results show that 51% (+/- 0.5%) would vote Democrat. Answer the following question, and explain your reasoning.

What are your observational units in this study?

Answer 8

The observational unit is the unit for which data is being recorded; each observational unit has its own value for a variable. In this case, data is being collected on the voting preference of U.S. voters; this makes them the observational units of this study.

Question 8

HW Series 3: Practice

1b

Answer 8

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Question 9

HW Series 2: Practice

9b

Answer 9

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Question 10

HW Series 3: Lab

5

Answer 10

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Question 11

HW Series 2: Lab

4a

Answer 11

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Question 11

HW Series 3: Lab

2b

Answer 11

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Question 12

Lec 3 PS

1d

Answer 12

See notes

Question 12

HW Series 2: Lab

9d

Answer 12

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Question 13

# HW Series 2: Practice 9a

Answer 13

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Question 14

# HW Series 2: Practice 10

Answer 14

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Question 14

# HW Series 3: Lab 3a

Answer 14

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Question 15

# HW1 Lab Problems 4b

Answer 15

See solutions

Question 16

# HW Series 3: Lab 2a

Answer 16

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Question 17

# HW Series 3: Practice 8iv

Answer 17

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Question 17

# HW Series 2: Practice 5c

Answer 17

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Question 18

# HW Series 2: Practice 4b

Answer 18

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Question 19

# HW Series 2: Lab 5d

Answer 19

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Question 20

# HW1 Lab Problems 1b

Answer 20

See solutions

Question 21

# HW Series 3: Practice 1a

Answer 21

See key

Question 22

# HW Series 2: Lab 1d

Answer 22

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Question 23

# HW Series 2: Lab 6b

Answer 23

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Question 23

# HW Series 2: Practice 6a

Answer 23

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Question 24

# HW1 Lab Problems 5b

Answer 24

See solutions

Question 25

# HW Series 3: Practice 2b

Answer 25

See key

Question 27

# HW1 Lab Problems 5c

Answer 27

See solutions

Question 28

# HW Series 2: Practice 9c

Answer 28

See key

Question 29

# HW1 Practice Probs 9c

Answer 29

See HW1 Practice Problem Solutions

Question 29

# HW Series 3: Practice 10

Answer 29

See key

Question 29

# HW Series 2: Practice 8a

Answer 29

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Question 30

# HW Series 2: Practice 6b

Answer 30

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Question 31

# Define a **confounding variable**.

Answer 31

A variable which correlates (either positively *or* negatively) with both the independant and dependant variables.

Question 32

# HW1 Lab Problems 2b

Answer 32

See solutions

Question 32

# HW Series 2: Practice 3

Answer 32

See key

Question 33

# HW Series 2: Practice 1d

Answer 33

See key

Question 33

# HW Series 2: Practice 8b

Answer 33

See key

Question 34

# Lec 3 PS 2e

Answer 34

See notes

Question 35

# HW Series 2: Practice 9d

Answer 35

See key

Question 36

# HW Series 2: Practice 9a

Answer 36

See key

Question 37

# HW Series 2: Lab 9c

Answer 37

See key

Question 38

# HW1 Practice Probs 5

Answer 38

See HW1 Practice Problem Solutions

Question 38

# HW Series 2: Practice 6a

Answer 38

See key

Question 39

# HW Series 2: Lab 5a

Answer 39

See key

Question 40

# HW Series 2: Practice 2b

Answer 40

See key

Question 41

# HW Series 2: Practice 1c

Answer 41

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Question 42

# Lecture 2 You poll 1000 U.S. voters and ask them if they will vote Democrat or Republican in the upcoming national election. Your results show that 51% (+/- 0.5%) would vote Democrat. Answer the following question, and explain your reasoning. What is your **statistical inference**?

Answer 42

**Statistical inference** is the conclusion you make based upon your results. Since the majority of people said they would vote Democrat and the level of uncertainty is not high enough to change this, your statistical inference would be that **Democrats will win the upcoming election**.

Question 43

# HW Series 2: Practice 1d

Answer 43

See key

Question 44

# Lecture 2 Define a **latent variable**.

Answer 44

Variables that are not directly observed, but can be inferred from other observeable variables.

Question 45

# HW1 Practice Probs 9b

Answer 45

See HW1 Practice Problem Solutions

Question 45

# HW Series 3: Practice 3b

Answer 45

See key

Question 47

# HW Series 3: Lab 4a - vi

Answer 47

See key

Question 48

# HW Series 2: Practice 5a

Answer 48

See key

Question 49

# Lec 3 PS 1c

Answer 49

See notes

Question 51

# HW Series 2: Lab 9a

Answer 51

See key

Question 52

# HW1 Lab Problems 3c

Answer 52

See solutions

Question 53

# HW Series 3: Practice 5b

Answer 53

See key

Question 54

# HW Series 2: Lab 10

Answer 54

See key

Question 56

# Lec 3 PS 1e

Answer 56

See notes

Question 57

# HW Series 2: Practice 3

Answer 57

See key

Question 59

# HW Series 3: Lab 3b

Answer 59

See key

Question 60

# HW1 Practice Probs 4b

Answer 60

See HW1 Practice Problem Solutions

Question 61

# HW Series 2: Lab 7

Answer 61

See key

Question 63

# HW Series 2: Practice 2c

Answer 63

See key

Question 63

# HW Series 3: Lab 4a - iv

Answer 63

See key

Question 65

# HW1 Lab Problems 1a

Answer 65

See solutions

Question 66

# HW Series 3: Practice 6b

Answer 66

See key

Question 67

# HW Series 3: Practice 9

Answer 67

See key

Question 68

# HW Series 2: Practice 1b

Answer 68

See key

Question 69

# HW Series 3: Lab 4a - ii

Answer 69

See key

Question 70

# HW Series 2: Practice 2c

Answer 70

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Question 71

# HW Series 2: Practice 9d

Answer 71

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Question 72

# Lecture 2 1. Describe a **categorical variable**. 2. Give an example and explain.

Answer 72

A variable that can take on a fixed of limited amount of values that cannot be quantified (i.e. there is no "amount" of that variable). An example would be voting preference of voters.

Question 72

# HW Series 2: Practice 4a

Answer 72

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Question 73

# HW Series 2: Practice 2a

Answer 73

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Question 73

# HW Series 3: Practice 5c

Answer 73

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Question 74

# HW Series 2: Lab 9b

Answer 74

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Question 75

# HW Series 2: Practice 1b

Answer 75

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Question 76

# Lecture 2 1. Describe a **quantitative variable**. 2. Give an example and explain.

Answer 76

1. A variable that can be quantified or measured on a numerical scale. 2. An example would be height or weight.

Question 78

# Lecture 2 1. Bar and pie plots are used to visualize __________ variables.

Answer 78

**Categorical** variables

Question 79

# HW1 Practice Probs 1a

Answer 79

See HW1 Practice Problem Solutions

Question 80

# HW Series 3: Lab 1a

Answer 80

See key

Question 80

# HW Series 2: Practice 1a

Answer 80

See key

Question 81

# Lec 3 PS 2b

Answer 81

See notes

Question 82

# HW Series 2: Lab 3

Answer 82

See key

Question 84

# HW1 Practice Probs 1c

Answer 84

See HW1 Practice Problem Solutions

Question 86

# HW1 Lab Problems 1c

Answer 86

See solutions

Question 88

# Lecture 2 You have a data set of the numbers 1, 1, 2, 3, 3, 5, and 12. Without calculating, which will be higher, the median or the mean?

Answer 88

The **mean** will be higher since the outlier, 12, will cause the mean to shift upwards. The **median** will not be as affected by the outlier. Calculated: Mean = 4.5 Median = 3

Question 90

# HW Series 3: Lab 4a - i

Answer 90

See key

Question 91

# HW Series 2: Practice 1c

Answer 91

See key

Question 92

# HW Series 2: Practice 9b

Answer 92

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Question 94

# HW Series 3: Practice 5a

Answer 94

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Question 95

# HW Series 2: Lab 2b

Answer 95

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Question 96

# Define a **population**.

Answer 96

Set of individuals of interest. Also the group from which all possible samples can be drawn.

Question 97

# Lecture 2 1. Describe a **continuous variable**. 2. Give an example and explain.

Answer 97

1. A continuous variable is a type of quantitative variable that can have a "fraction" value between whole values. 2. Examples include height (1' = 12"), weight (fractions of a pound), and temperature (fractions of a degree).

Question 98

# Lecture 2 You poll 1000 U.S. voters and ask them if they will vote Democrat or Republican in the upcoming national election. Your results show that 51% (+/- 0.5%) would vote Democrat. Answer the following question, and explain your reasoning. What is your **sample** in this study?

Answer 98

The **sample** is a group that is drawn from the population and is the group on which data is collected. In this case, your sample is the **1000 U.S. voters** polled out of the population of *all* U.S. voters.

Question 100

# HW1 Practice Probs 9a

Answer 100

See HW1 Practice Problem Solutions

Question 101

# HW Series 2: Practice 5d

Answer 101

See key

Question 102

# HW Series 2: Lab 8b

Answer 102

See key

Question 103

# Lec 3 PS 2d

Answer 103

See notes

Question 104

# HW Series 2: Practice 10

Answer 104

See key

Question 105

# HW Series 2: Practice 6b

Answer 105

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Question 107

# HW Series 3: Practice 3a

Answer 107

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Question 108

# HW Series 2: Practice 5d

Answer 108

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Question 110

# HW Series 2: Lab 4b

Answer 110

See key

Question 111

# HW Series 2: Practice 5b

Answer 111

See key

Question 112

# HW1 Lab Problems 1d

Answer 112

See solutions

Question 113

# Lecture 2 You poll 1000 U.S. voters and ask them if they will vote Democrat or Republican in the upcoming national election. Your results show that 51% (+/- 0.5%) would vote Democrat. Answer the following question, and explain your reasoning. What is the **variable** being examined in this study?

Answer 113

The **variable** is the value or characteristic of each observational unit that is being examined, and can change between observational units. In this case, the characteristic being examined is the **voting preference** of U.S. voters (the observational units).

Question 114

# HW Series 2: Lab 2a

Answer 114

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Question 115

# HW Series 2: Lab 1c

Answer 115

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Question 116

# HW Series 2: Lab 2c

Answer 116

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Question 117

# HW1 Practice Probs 4a

Answer 117

See HW1 Practice Problem Solutions

Question 119

# HW Series 3: Practice 4b

Answer 119

See key

Question 120

# Lec 3 PS 1f

Answer 120

See notes

Question 121

# Lecture 2 You poll 1000 U.S. voters and ask them if they will vote Democrat or Republican in the upcoming national election. Your results show that 51% (+/- 0.5%) would vote Democrat. Answer the following question, and explain your reasoning. What is the **population** of this study?

Answer 121

The **population** is the group from which all possible samples can be drawn. Since your sample in this case was 1000 U.S. voters, your population would be **all U.S. voters**.

Question 122

# HW1 Lab Problems 3a

Answer 122

See solutions

Question 123

# Lec 3 PS 2a

Answer 123

See notes

Question 124

# HW Series 3: Lab 4b - ii

Answer 124

See key

Question 126

# HW Series 2: Practice 5c

Answer 126

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Question 128

# HW Series 2: Lab 5c

Answer 128

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Question 129

# HW Series 3: Practice 4a

Answer 129

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Question 131

# HW Series 3: Lab 4a - iii

Answer 131

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Question 133

# HW Series 3: Practice 8iii

Answer 133

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Question 134

# HW Series 2: Practice 4b

Answer 134

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Question 136

# Lecture 2 Explain the difference between **confounding** **va****riable**and a**latent variable**.

Answer 136

None yet! Waiting for email from Professor Aue.

Question 138

# HW Series 3: Practice 2c

Answer 138

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Question 140

# Lecture 2 Explain how height and age could be both a **continuous** or a **discrete.**

Answer 140

They can both be **continuous** in the sense that you can break them down into smaller units; inches can be broken down into fractions of inches, and age can be broken down into months, weeks and days. *However*, they could also be **discrete** in the sense that both are not usually reported with fractions; if you were to ask someone their height, they would respond with feet and inches, not fractions of inches. Likewise, if you were to ask someone their age, they would respond with years, not years, months, weeks, and days (unless they were a baby!).

Question 141

# HW Series 2: Practice 2a

Answer 141

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Question 143

# HW Series 2: Lab 1a

Answer 143

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Question 144

# Lec 3 PS 2f

Answer 144

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Question 144

# HW Series 3: Lab 4b - i

Answer 144

See key

Question 145

# HW Series 2: Lab 6a

Answer 145

See key

Question 146

# HW1 Practice Probs 7

Answer 146

See HW1 Practice Problem Solutions

Question 148

# HW Series 2: Lab 1b

Answer 148

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Question 149

# Lecture 2 (T/F): the mean will always differ from the median

Answer 149

**False** You can create a data set where the mean and median are the same, e.g. 1, 2, 3, 4, 5. Both the mean and median for this set are 3. Another example would be a data set where all values are the same, e.g. 1, 1, 1, 1, 1. Both the mean and median would be the same, and so would the mode.

Question 150

# HW Series 2: Practice 9c

Answer 150

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Question 151

# HW Series 3: Practice 2a

Answer 151

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Question 152

# Lec 3 PS 2c

Answer 152

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Question 153

# Lecture 2 Explain the advantages & disadvantages of using the median to calculate the middle value for a data set vs. using the mean to calcuate the middle value.

Answer 153

One advantage is that the median is not as affected by outliers, and tends to give a better middle value for "normal" observational units. e.g. for calculating income in the U.S., the mean would give a much higher middle-value income than the median due to a small group of people having extremely large incomes. Thus, middle-value income is reported as the median income. Disadvantages to come.

Question 154

# HW Series 2: Practice 2b

Answer 154

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Question 155

# HW Series 3: Practice 8i

Answer 155

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Question 156

# HW1 Practice Probs 2c

Answer 156

See HW1 Practice Problem Solutions

Question 157

# HW Series 2: Practice 1a

Answer 157

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Question 158

# HW Series 2: Practice 4a

Answer 158

See key

Question 159

# HW1 Lab Problems 5a

Answer 159

See solutions

Question 160

# HW1 Practice Probs 6b

Answer 160

See HW1 Practice Problem Solutions

Question 161

# HW Series 2: Practice 5b

Answer 161

See key

Question 162

# HW Series 3: Lab 4a - v

Answer 162

See key

Question 163

# HW1 Practice Probs 8

Answer 163

See HW1 Practice Problem Solutions

Question 164

# HW1 Practice Probs 3

Answer 164

See HW1 Practice Problem Solutions

Question 165

# HW1 Practice Probs 4c

Answer 165

See HW1 Practice Problem Solutions

Question 166

# HW Series 3: Practice 6a

Answer 166

See key

Question 167

# HW Series 2: Practice 7

Answer 167

See key

Question 168

# HW1 Practice Probs 2b

Answer 168

See HW1 Practice Problem Solutions

Question 169

# Lecture 2 1. Describe an **ordinal variable**. 2. Give an example and explain.

Answer 169

1. An ordinal variable is a categorical variable for which the possible values are arbitrarily ordered. 2. An example would be assigning numeric values to voting preferences - say 1 for Democrat and 0 for Republican.

Question 170

# HW Series 2: Practice 5a

Answer 170

See key

Question 171

# Lec 3 PS 1g

Answer 171

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