Stat 200 Test 1

Front 1

What is the population?

Back 1

All individuals of interest

Front 2

What is a sample?

Back 2

The individuals studied.

Front 3

List three problems with using the number 868/1523 (obtained from a Gallup poll) for the probability that all adults bought a lottery ticket last year. _____, might be a bad sample, people might lie or forget

Back 3

only a sample

Front 4

List three problems with using the number 868/1523 (obtained from a Gallup poll) for the probability that all adults bought a lottery ticket last year._____, only a sample, people might lie or forget

Back 4

might be a bad sample

Front 5

List three problems with using the number 868/1523 (obtained from a Gallup poll) for the probability that all adults bought a lottery ticket last year. ______, only a sample, might be a bad sample.

Back 5

people might lie or forget

Front 6

If the sample size in the Gallup poll went from 1523 to 6523 will the percentage that said they bought a lottery ticket most likely go up, most likely go down, or can you not tell?

Back 6

can’t tell

Front 7

If you take two samples of the same size from the same population will the percentage that bought a lottery ticket be the same?

Back 7

probably not

Front 8

Which is likely to be closer? The percentages in two samples of size 5 from the same population, or the percentages in two samples of size 500 from the same population?

Back 8

500

Front 9

In a discrete probability model all the probabilities of all the outcomes add up to what number?

Back 9

1

Front 10

In a continuous probability model what adds up to 1?

Back 10

total area

Front 11

Three ways of determining probability are ________, theory, and guess.

Back 11

experiment

Front 12

Three ways of determining probability are ________, experiment, and guess.

Back 12

theory

Front 13

Three ways of determining probability are ________, theory, and experiment.

Back 13

guess

Front 14

If someone gives you a coin, can you find exactly the probability it will land heads?

Back 14

no

Front 15

Suppose I give you a bent coin, how can you estimate the probability it will land heads?

Back 15

toss it many times (experiment!)

Front 16

Chance behavior has what property in the short run?

Back 16

unpredictable

Front 17

Chance behavior has what property in the long run?

Back 17

predictable

Front 18

When observing, do people tend to see the long run?

Back 18

no

Front 19

When observing, do people tend to give equal importance to all outcomes?

Back 19

no

Front 20

When observing, which outcomes do people tend to give more importance to?

Back 20

remarkable ones

Front 21

Suppose airline A has three times as many flights out of a city than airline B which will have a higher percent of delayed flights? Most likely A, most likely B or you have no idea.

Back 21

no idea

Front 22

What is the notation for the population mean?

Back 22

Front 23

The variance and standard deviation measure what?

Back 23

how the data is spread out

Front 24

The mean measures what?

Back 24

the middle of the data

Front 25

What is the notation for population variance?

Back 25

Front 26

What is the notation for population standard deviation?

Back 26

Front 27

What is the area under the z curve?

Back 27

1

Front 28

What is the mean of the z curve?

Back 28

0

Front 29

What is the standard deviation of the z curve?

Back 29

1

Front 30

What is the formula for the z curve?

Back 30

Front 31

Describe how far a standard deviation is on the z curve.

Back 31

horizontal distance from the top to where the slope is getting less steep instead of steeper

Front 32

On the z curve how much of the data is within 1 standard deviation of the mean?

Back 32

about 68%

Front 33

On the z curve how much of the data is within 2 standard deviations of the mean?

Back 33

about 95%

Front 34

On the z curve how much of the data is within 3 standard deviations of the mean?

Back 34

about 99.7%

Front 35

For any probability distribution how much of the data is within 1 standard deviation of the mean?

Back 35

can’t say anything

Front 36

For any probability distribution how much of the data is within 2 standard deviations of the mean?

Back 36

at least 75%

Front 37

For any probability distribution how much of the data is within 3 standard deviations of the mean?

Back 37

at least 88.8%

Front 38

What is a parameter?

Back 38

number that describes the population

Front 39

What is a statistic?

Back 39

number that describes a sample

Front 40

Most often what is calculated, a parameter or a statistic?

Back 40

statistic

Front 41

What is the notation for the sample mean?

Back 41

Front 42

What is the notation for the sample standard deviation?

Back 42

Front 43

What is the notation for the sample variance?

Back 43

Front 44

Back 44

Front 45

Back 45

Front 46

Back 46

large

Front 47

If you flip a fair coin and record the percentage of heads, you will get close to 50% by luck and __________.

Back 47

large sample size

Front 48

If you flip a fair coin and record the percentage of heads, you will get close to 50% by _____ and having a large sample size.

Back 48

luck

Front 49

If you flip a fair coin 10 times and get close to 50% it will be mostly due to what?

Back 49

luck

Front 50

If you flip a fair coin 1000 times and get close to 50% it will be mostly due to what?

Back 50

large sample size

Front 51

Back 51

Front 52

Back 52

Front 53

For large samples is there much difference between sampling with and without replacement.

Back 53

no

Front 54

If the original data is normal, what about the shape of all sample means from samples of the same size?

Back 54

normal

Front 55

If the original data is not normal, what happens to the shape of all sample means from samples of size n as n goes up?

Back 55

gets closer to normal

Front 56

What is the name of the theorem that says as the sample size goes up that the sample means become closer to normal?

Back 56

Central Limit Theorem

Front 57

Consider data setsA:{25,26,26,25,24} and B:{15,25,38,22,40}. If you know one set of data is 5 individuals and the other is 5averages, which is more likely to be the 5 averages? _____.

Back 57

A

Front 58

Consider data setsA:{25,26,26,25,24} and B:{15,25,38,22,40}. If you know one set of data is 5 individuals and the other is 5averages, A is more likely to be the 5 averages? This is because the ___________ __________of averages is smaller.

Back 58

standard deviation

Front 59

Consider data setsA:{25,26,26,25,24} and B:{15,25,38,22,40}. If you know one set of data is 5 individuals and the other is 5averages, A is more likely to be the 5 averages? This is because the standard deviation ofaverages is _________.

Back 59

smaller

Front 60

Explain why it makes sense that averages tend to have a smaller standard deviation than individuals?

Back 60

highs and lows tend to cancel out

Front 61

Back 61

Front 62

Back 62

Front 63

Back 63

smaller

Front 64

What does the z score tell us in terms of standard deviation?

Back 64

how many standard deviations from the mean

Front 65

Is it human nature to tend to pay more attention to anecdotes or all the data?

Back 65

anecdotes

Front 66

Which is more important to pay attention to, anecdotes or all the data?

Back 66

all the data

Front 67

Give an example of how data beat anecdotes.

Back 67

looking at all the data about child and leukemia and power lines instead of news interview of one mother with child with leukemia that happens to live near a power a line

Front 68

What is a lurking variable?

Back 68

a variable that affects the variables you are interested in but is not mentioned

Front 69

Give an example of lurking variable.

Back 69

child in soccer have higher school scores, but a LV is how much the parents want their kids to succeed, if they want their kids to succeed a lot then they will be more likely to put them in soccer and also do things such as to encourage them to study

Front 70

Why does the following graph make it look likedrivers under 25 are the worst?

Back 70

the under 25 has a lot more drivers

Front 71

Two problems with the graph are the y-axis startat 0 and ____________.

Back 71

we don’t know how the data was obtained

Front 72

Two problems with the graph are we don’t how thedata were obtained and _______.

Back 72

the y-axis does not start at 0

Front 73

Why do we do statistical graphs?

Back 73

to understand the data

Front 74

Let’s compare percent of children abused in Idaho and Virginia. In Idaho its 22.6% and in Virginia its only 5.9%. Does this mean it is safer for children in Virginia? Explain.

Back 74

no, definition of child abuse could be different

Front 75

How is it that in 1998 North Dakota that was 45th in spending per pupil has a much higher SAT average (by almost 200 points) than New Jersey that was 2nd in spending per pupil?

Back 75

mostly the best students in North Dakota take the SAT while in New Jersey a much higher percent take the SAT

Front 76

Suppose in a big city it is found that in all fatal car accidents 25% were under the influence of alcohol and 75% were not. It seems that it is better to be drunk, explain why it is not the case.

Back 76

there are many more drivers not drinking so they could easily have more accidents

Front 77

Are statistical conclusions about populationsbased on samples ever 100% sure?

Back 77

no

Front 78

A good graph will show that many people mostlikely in Florida voted for whom by mistake in 2000?

Back 78

Buchanan

Front 79

In a CI as the confidence level goes up, what happens to the margin of error?

Back 79

up

Front 80

In a CI as the sample size goes up, what happens to the margin of error?

Back 80

down

Front 81

In a CI if the standard deviation gets higher, what happens to the margin of error?

Back 81

up

Front 82

All things being equal, do we prefer the margin of error to be big or small?

Back 82

small

Front 83

Back 83

40

Front 84

Back 84

Front 85

Back 85

normal

Front 86

Is the z distribution symmetric?

Back 86

yes

Front 87

Is the mean sensitive to outliers?

Back 87

yes

Front 88

Is the standard deviation sensitive to outliers?

Back 88

yes

Front 89

Is the median sensitive to outliers?

Back 89

no

Front 90

Are the quartiles sensitive to outliers?

Back 90

no

Front 91

Suppose you have data only summarized in different numerical ranges. How can you estimate the mean and standard deviation?

Back 91

assume the data are the midpoints of the ranges