Exam 1

Question 1

A random variable is denoted by a _____ letter, while an observed value of that variable is denoted by a _____ letter.

Answer 1

Capital; lower case

Question 2

Probability of E1 does not affect probability of E2.

Answer 2

Independence

Question 3

Experimental studies

Answer 3

Condition is randomly assigned to groups and condition is compared.

Question 4

Random sample

Answer 4

A sample in which each subject has an equally likely chance to be selected as anyone in the population.

Question 5

A subset of the population

Answer 5

Sample

Question 6

Surveys

Answer 6

Self-collected data form in which subjects are not manipulated.

Question 7

A numerical variable which has a natural zero starting point and differences in values are meaningful.

Answer 7

Ratio

Question 8

The formulas for determining the upper and lower fences for outliers.

Answer 8

Lower: Q1 - 1.5(IQR)
Upper Q3 + 1.5(IQR)

Question 9

With independence, what is different about conditionals?

Answer 9

They do not apply, because the probability remains unchanged by the condition.

Question 10

Data that is naturally labeled or in categories.

Answer 10

Categorical data

Question 11

What is the relationship between the measures of center in a normal distribution?

Answer 11

Mean = median = mode

Question 12

Self-collected data form in which subjects are not manipulated.

Answer 12

Surveys

Question 13

Observational studies

Answer 13

Groups of participants are observed but not manipulated.

Question 14

Sample

Answer 14

A subset of the population

Question 15

Ratio

Answer 15

A numerical variable which has a natural zero starting point and differences in values are meaningful.

Question 16

Symmetric

Answer 16

Equal amount of spread to the left and right of the center.

Question 17

What is the relationship between the measures of center in a bimodal distribution?

Answer 17

Mean = median

Question 18

A variable that varies because of a random component.

Answer 18

Random variable

Question 19

A numerical variable which has no meaningful natural zero starting point and differences between values are meaningful.

Answer 19

Interval

Question 20

A sample in which each subject has an equally likely chance to be selected as anyone in the population.

Answer 20

Random sample

Question 21

A characteristic of a subject that varies from subject to subject.

Answer 21

Variable

Question 22

Confounding variables.

Answer 22

Unknown or unmeasured variables which could affect the variable of interest.

Question 23

Law of Large Numbers

Answer 23

As n approaches infinity, sample probability/frequency approaches population probability.

Question 24

A numerical variable that has natural gaps.

Answer 24

Discrete

Question 25

"Skew" refers to the side of the distribution in which the _____ lies.

Answer 25

Tail

Question 26

(T/F) In a distribution that is skewed left, the bulk of observations lie to the left.

Answer 26

F

Question 27

(T/F) In a distribution that is skewed left, the bulk of observations lie to the right.

Answer 27

T

Question 28

The formula for finding the quartiles.

Answer 28

Location (when arranged in ascending order): L = (%)(n+1) If between two values, find mean of the two.

Question 29

Nominal

Answer 29

A categorical variable which has no natural rank or order.

Question 30

Independence

Answer 30

Probability of E1 does not affect probability of E2.

Question 31

Law of Total Probability

Answer 31

Pr{E1} = Pr{E1 AND E2} + Pr{E1 AND E2^c}

Question 32

Ordinal

Answer 32

A categorical variable which has a natural ordering.

Question 33

Complement of a conditional

Answer 33

Pr{E1|E2} = 1 - Pr{E1^c|E2}

Question 34

Subject

Answer 34

A person/place/thing that we measure data from.

Question 35

Population

Answer 35

All subjects we are interested in.

Question 36

Intervals in a histogram (include/exclude) the lowest value and (include/exclude) the highest value.

Answer 36

Exclude; include

Question 37

Deviation

Answer 37

The difference between the observed value and the sample mean. y_i - ybar

Question 38

How to prove independence.

Answer 38

Prove all three: Pr{A AND B} = Pr{A}Pr{B} Pr{A|B} = Pr{A} Pr{B|A} = Pr{B}

Question 39

Discrete

Answer 39

A numerical variable that has natural gaps.

Question 40

A categorical variable which has no natural rank or order.

Answer 40

Nominal

Question 41

How to prove dependence.

Answer 41

Disprove one: Pr{A AND B} = Pr{A}Pr{B} Pr{A|B} = Pr{A} Pr{B|A} = Pr{B}

Question 42

Data that is naturally measured as a number

Answer 42

Numerical data

Question 43

Continuous

Answer 43

A numerical variable that can have an infinite number of values within an interval.

Question 44

Groups of participants are observed but not manipulated.

Answer 44

Observational studies.

Question 45

Interval

Answer 45

A numerical variable which has no meaningful natural zero starting point and differences between values are meaningful.

Question 46

Random variable

Answer 46

A variable that varies because of a random component.

Question 47

Simple random sample

Answer 47

A sample in which every group of a particular size n has the same chance of being selected.

Question 48

Disjoint

Answer 48

Mutually exclusive; events cannot occur at the same time or they have no elements in common. Pr{A AND B} = 0

Question 49

Numerical data

Answer 49

Data that is naturally measured as a number

Question 50

A numerical variable that can have an infinite number of values within an interval.

Answer 50

Continuous

Question 51

Condition is randomly assigned to groups and condition is compared.

Answer 51

Experimental studies

Question 52

Variable

Answer 52

A characteristic of a subject that varies from subject to subject.

Question 53

A person/place/thing that we measure data from.

Answer 53

Subject

Question 54

Mutually exclusive; events cannot occur at the same time or they have no elements in common. Pr{A AND B} = 0

Answer 54

Disjoint

Question 55

Equal amount of spread to the left and right of the center.

Answer 55

Symmetric

Question 56

Unknown or unmeasured variables which could affect the variable of interest.

Answer 56

Confounding variables.

Question 57

A sample in which every group of a particular size n has the same chance of being selected.

Answer 57

Simple random sample

Question 58

Coefficient of variation

Answer 58

The ratio of StDev to the mean. (StDev/mean) * 100

Question 59

Pr{E1} = Pr{E1 AND E2} + Pr{E1 AND E2^c}

Answer 59

Law of Total Probability

Question 60

All subjects we are interested in.

Answer 60

Population

Question 61

Categorical data

Answer 61

Data that is naturally labeled or in categories.