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Statistics > Chapters 1-3 > Flashcards

Chapters 1-3 Flashcards

1
Q

What type of sample is generally not suitable?

A

Voluntary Response Sample

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2
Q

Define data

A

Observations that are collected

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3
Q

Define statistics

A

What is done with the data

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4
Q

Define population

A

The complete set of all elements being studied

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5
Q

Define sample

A

A subset of a population

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6
Q

Define census

A

Collection of every member in a population

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7
Q

Define parameter

A

Characteristic of a population

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8
Q

Define statistic

A

Characteristic of a sample

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9
Q

What are the four levels of measurement

A

Ordinal, nominal, interval, ratio

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10
Q

Define nominal and give an example

A

Cannot put in any order. Consists of names, labels, or categories. Example: race, gender

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11
Q

Define ordinal

A

Can be arranged, differences are meaningless. Example: ranks

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12
Q

Define interval

A

Can be arranged, differences are meaningful, no natural 0 Example: temperature

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13
Q

Define observational study

A

No modification of subjects, strictly observation

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14
Q

Define experimental study

A

Apply treatment then measure the effect on the subject

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15
Q

Define simple random sample

A

Subjects collected in such a way that each member of a sample size “n” has an equal chance of being selected

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16
Q

Define systematic sampling

A

Select some starting point then select every “kth” element in the population

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17
Q

Define convenience sampling

A

Results that are easy to get

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18
Q

Define stratified sampling

A

Subdivide the population into at least two different sub groups so that subjects within the same subgroup share the same characteristics then draw a sample from each subgroup

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19
Q

Define cluster sampling

A

Divide the population into clusters then randomly select some of those clusters then choose all members from the selected clusters

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20
Q

Define retrospective study

A

Go back in time to collect data over some past period

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21
Q

define cross-sectional study

A

Data are measured at one point in time

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22
Q

Define prospective study

A

Go forward in time and observe groups sharing common factors

23
Q

Define completely randomized experimental design

A

Assign subjects to different treatment groups through s progress of random selection

24
Q

Define randomized block design

A

A block is a group of subjects that are similar but bLocks differ in ways that might affect the outcome of the experiment

25
Q

Define matched pairs design

A

Before/ after comparison or twins

26
Q

In a study of the Marisa Waite diet, four subjects lost an average of 45 pounds. It is found that there is about a 30% chance of getting such results with a diet that has no effect. Determine if it has practical and/or statistical significance.

A

No statistical significance but there is practical significance.

27
Q

Is there some meaningful way in which the IQ scores are matched with the corresponding brain volumes? Is they are matched, does it make sense to use the difference between each IQ score and the brain volume that is in the same column?

A

the meaningful way is that it is the same person and it doesn’t make sense to take the difference bc the two have different units

28
Q

Define discrete data

A

Data values are quantitative and the number of values is finite or “countable”

29
Q

Define continuous data

A

Results are infinitely quantitative

30
Q

The mean IQ score for subjects taking the Wechsler Adult Intelligence Scale IQ tests is 100: statistic or parameter?

A

Parameter

31
Q

Determine which of the four levels of measurement is appropriate: colors of m&ms in data set 20 in appendix B

A

Nominal

32
Q

Determine which of the four levels of measurement is appropriate: years in which US presidents were inaugurated

A

Interval

33
Q

Determine which of the four levels of measurement is appropriate: volumes of brains

A

Ratio

34
Q

Identify which type of sampling is used: random, systematic, convenience, stratified, or cluster: the author collected sample data by randomly selecting 12 different pages from Harry Potter and the Sorcerers Stone and then finding the number of words in each sentence of those pages

A

Cluster

35
Q

Identify which type of sampling is used: random, systematic, convenience, stratified, or cluster: in a new pew research center poll, 1007 adults were called after their telephone numbers were randomly generated by computer, and 85% of the respondents were able to correctly identify what Twitter is

A

Random

36
Q

Identify which type of sampling is used: random, systematic, convenience, stratified, or cluster: The CBS News station in New York City often obtains opinions by interviewing neighbors of a person who is the focus of a new story

A

Convenience

37
Q

Identify which type of sampling is used: random, systematic, convenience, stratified, or cluster: satellites are used to collect sample data used to estimate Deforestation rates. The forest resources assessment of the UN food and agriculture organization uses a method of selecting a sample of a 10 km white square every 1° intersection of latitude and longitude

A

Systematic

38
Q

Identify which type of sampling is used: random, systematic, convenience, stratified, or cluster: The author collected sample data by randomly selecting 20 different pages from a printed version of the Merriam Webster dictionary and then counting the number of defined words on each of those pages

A

Cluster

39
Q

Identify which type of sampling is used: random, systematic, convenience, stratified, or cluster: in a clinical trial of the cholesterol drug Lipitor, subjects were partitioned into groups given a placebo or a Lipitor doses of 10 mg, 20 mg, 40 mg, or 80 mg. The subjects were randomly assigned to the different treatment groups

A

Random

40
Q

Identify which type of sampling is used: random, systematic, convenience, stratified, or cluster: in 1936 literary digest magazine mailed questionnaires to 10 million people and obtain 2 million responses. The responses indicated that Alf Landon would win the presidential election but Franklin D Roosevelt actually won the election

A

Convenience

41
Q

Identify which type of sampling is used: random, systematic, convenience, stratified, or cluster: The New York State Department of Transportation evaluated the quality of New York State Throughway by testing course samples collected at regular intervals of 1 mile

A

Systematic

42
Q

Identify which of these designs is most appropriate for the given experiment: completely randomized design, randomized block design, or matched pairs design: Lisinopril is a drug design to lower blood pressure. In a clinical trial of lisinopril, blood pressure levels of subjects are measured before and after they have been treated with the drug

A

Matched pairs design

43
Q

Identify which of these designs is most appropriate for the given experiment: completely randomized design, randomized block design, or matched pairs design: The HIV trials network is conducting a study to test the effectiveness of two different experimental HIV vaccines. Subject will consist of 80 pairs of twins. For each pairs of twins one of the subjects will be treated with the DNA vaccine and the other twin will be treated with the adenoviral vector vaccine

A

Matched pairs design

44
Q

What is the formula for class width

A

[(maximum data value)-(minimum data value)]/ number of classes

45
Q

How do you find class boundaries

A

Upper class limit + next lower class limit in total divided by 2

46
Q

What are the class midpoints

A

The values in the middle of the classes. Add the lower class limit to the upper class limits and divide the sum by two

47
Q

Define skewed to the right and skewed to the left

A

Skewed to the right means there is a longer tail on the right side of the graph and skewed to the left means that there is a longer tail on the left side of the graph

48
Q

How do you find the mid range of a data set

A

Add the maximum data value to the minimum data value and divide the sum by two

49
Q

How do you find the range of a data set

A

Take the maximum data value and subtract the minimum data value

50
Q

What is one of the formulas for standard deviation

A

The square root of the sum of X minus X bar squared over n-1

51
Q

What is the variance

A

The variance is the square of the standard deviation

52
Q

What is the empirical rule

A

68% of data is one standard deviation from the mean. 95% of data is within two standard deviation’s of the mean. 99.7% of data is three standard deviation from the mean

53
Q

What is the Z score and how do you find it

A

Something that allows us to compare two sets of data. It is the number of standard deviation from the mean a special data value is. Z equals X minus the mean divided by the sample size

54
Q

What is the usual and unusual Z score

A

Usual means the Z score is between -2 and two. Unusual is anything outside of these values

Statistics (3 decks)

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