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MAT 158 > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

measures the valve of the response variable without attempting to influence the value of wither the response or explanatory variables researcher observes the behavior of the individuals without trying to influence the outcome of the study

A

observational study

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2
Q

when the researcher signs the individuals in a study to a certain group, intentionally changes the value of the explanatory variable, and then records the value of the response variable for each group

A

designed experiments

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3
Q

a subset of a population

A

sample

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4
Q

the entire group to be studied

A

population

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5
Q

a person or object that is a member of the population being studied

A

individual

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6
Q

a numerical summary of a sample

A

statistic

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7
Q

consist of organizing and summarizing data

A

descriptive statistics

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8
Q

uses methods that take a result from a sample, extend it to the population, and measure the reliability of the result

A

inferential statistics

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9
Q

a numerical summary of a population

A

parameter

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10
Q

the characteristics of the individuals within the population

A

variables

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11
Q

allow for classification of individuals biased on some attribute or characteristic

A

qualitative, or categorical, variables

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12
Q

provide numerical measures of individuals; the values of this can be added or subtracted and provide meaningful results

A

quantitative variables

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13
Q

a way to look at and organize a problem so that it can be solved

A

approach

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14
Q

a quantitative variable that has either a finite number of possible values or a countable number of possible values; cannot take on every possible value between any two possible values

A

discrete variable

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15
Q

a quantitative variable that has a infinite number of possible values that are not countable; may take on every possible value between any two values

A

continuous variable

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16
Q

when the values of the variable name, label, or categorize; does not allow for the values of the variable to be arranged in a ranked or specific order

A

nominal level of measurement

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17
Q

a variable that has the properties of the nominal level of measurement, however the naming scheme allows for the values of the variable to be arranged in a ranked or specific order

A

ordinal level of measurement

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18
Q

a variable that has the properties of ordinal level of measurement and the differences in the values of the variable have meaning a value of zero does not mean the absence of the quantity; + and -

A

interval level of measurement

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19
Q

a variable that has rations of the values of the variable that have meaning; a value of zero means the absence of quantity; x and divide

A

ratio level of measurement

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20
Q

the information collected

A

explanatory variable

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21
Q

what is affected by the explanatory variable

A

response variable

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22
Q

this occurs in a study when the effects of two or more explanatory variables are not separated; meaning any relation that may exist between an explanatory variable and the response variable may be due to some other variable(s) not accounted for in the study

A

confounding

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23
Q

an explanatory variable that was not considered in a study, but it affects the value of the response variable in the study; typically related to explanatory variables considered in the study

A

lurking variable

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24
Q

These studies do not allow a researcher to claim causation, only association

A

observational studies

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25
Q

an explanatory variable that was considered in a study whose effect cannot be distinguished from a second explanatory variable in a study

A

confounding variable

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26
Q

these observational studies collect information about individuals at a specific point in time or over a very short period of time

A

cross-sectional studies

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27
Q

these observational studies are retrospective; look back in time or require the researcher to look at existing records; individuals who have a certain characteristic may be matched with those who do not

A

case-control studies

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28
Q

this observational study first identifies a group of individuals to participate in the study and then they are observed over a long period of time

A

cohort studies

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29
Q

a list of all individuals in a population along with certain characteristics of each individual

A

census

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30
Q

the process of using chance to select individuals from a population to be included in the sample

A

random sampling

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31
Q

a sample of size n from a population of size N is obtained through this if every possible sample size of size n has an equally likely chance of occurring

A

simple random sampling

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32
Q

the same that is taken from simple random sampling

A

simple random sample

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33
Q

the initial point for the generator to start creating random numbers

A

seed

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34
Q

an individual who is selected is removed from the population and cannot be chosen again

A

sample without replacement

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35
Q

a selected individual is placed back into the population and could be chosen a second time

A

sample with replacement

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36
Q

obtained by separating the population into non overlapping groups called strata and then obtaining a simple random sample from each stratum

A

stratified sample

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37
Q

obtained by selecting every kth individual from the population; the first individual selected corresponds to a random number between 1 and k

A

systematic sample

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38
Q

obtained by selecting al individuals within a randomly selected collection or group of individuals

A

cluster sample

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39
Q

a sample in which the individuals are easily obtained and not based on randomness

A

convenience sample

40
Q

the individuals themselves decide to participate in a survey

A

self-selected convenience sample

41
Q

lists each category of data and the number of occurrences for each category of data

A

frequency distribution

42
Q

the proportion (or percent) of observations within a category

A

relative frequency

43
Q

lists each category of data together with the relative frequency

A

relative frequency distribution

44
Q

constructed by labeling each category of data on either the horizontal or vertical axis and the frequency or relative frequency of the category on the other axis

A

bar graph

45
Q

a circle divided into sectors, where each sector represents a category of data; proportional to the frequency of the category

A

pie chart

46
Q

categories into which data are grouped; used when using continuous data

A

classes

47
Q

constructed by drawing rectangles for each class of data

A

histogram

48
Q

the smallest value within the class

A

lower class limit

49
Q

the largest value within the class

A

upper class limit

50
Q

the difference between consecutive lower class limits

A

class width

51
Q

a table is this if the first class as no lower class limit or the last class has no upper class limit; 40 or over

A

open ended

52
Q

a way to represent quantitative data graphically; where the digits to the left of the rightmost digit form the stem; the rightmost digit forms a leaf

A

stem-and-leaf plot

53
Q

created by placing each observation horizontally in increasing order and placing a dot above the observation each time it is observed

A

dot plot

54
Q

when the frequency of each value of the variable is evenly spread out across the values of the variable

A

uniform distribution

55
Q

when the highest frequency occurs in the middle and the frequencies tail off to the left and right of the middle

A

bell-shaped distribution

56
Q

when the tail to the right of the peak is loonier than the tail to the left of the peak

A

skewed right

57
Q

when the tail to the left of the peak is longer than the tail to the left of the peak

A

skewed left

58
Q

the sum of consecutive lower class limited divided by 2

A

class midpoint

59
Q

a graph that uses points, connected by line segments, to repress the frequencies for the classes

A

frequency polygon

60
Q

displays the aggregate frequency of the category; discrete - displays he total number of observations less than or equal to the category; continuous - displays the total number of observations less than or equal to the upper class limit of a class

A

cumulative frequency distribution

61
Q

displays the proportion (or percentage) of observations less than or equal to the category (discrete) or the upper class limit (continuous)

A

cumulative relative frequency distribution

62
Q

a graph that represents the cumulative (relative) frequency for the class; plots points whose x-coordinates are the upper class limits and whose y are the cumulative (relative) frequencies

A

ogive

63
Q

obtained by plotting the time in which a variable is measured on the horizontal axis and the corresponding value of the variable on the vertical axis; good for identifying trends over time

A

time-series plot

64
Q

computed by adding all the values of the variable in the data set and dividing by the number of observations

A

arithmetic mean

65
Q

computed using all the individuals in a population; µ

A

population arithmetic mean

66
Q

computed using sample data; a statistic; x-bar

A

sample arithmetic mean

67
Q

the value that lies in the middle of the data when arranged in ascending order; M

A

median

68
Q

a numerical summary is said to be this if extreme values (very large or small) relative to the data do not affect its value substantially

A

resistant

69
Q

the most frequent observation of the variable that occurs in a data set

A

mode

70
Q

occurs when no observation occurs more than once

A

no mode

71
Q

if a data set has 2 modes

A

bimodal

72
Q

if the data set has three or more modes

A

multimodal

73
Q

the degree to which the data are spread out

A

dispersion

74
Q

the difference between the largest and the smallest data value

A

range; R

75
Q

the ith observation minus the mean; the sum of all of these must equal zero

A

deviation about the mean

76
Q

the square root of the sum of squared standard deviations about the population mean divided by the number of observations in the population, N

A

population standard deviation

77
Q

the square root of the sum of squared deviations about the sample mean divided by n-1, where n is the sample size

A

sample standard deviation

78
Q

the square of the standard deviation

A

variance

79
Q

data that has been summarized in frequency distributions

A

grouped data

80
Q

a value such as k percent of the observations are less than or equal to the value

A

kth percentile; Pk

81
Q

divide data sets into fourths, or four equal parts

A

quartiles

82
Q

divides the bottom 25% of the data from the top 75%; 25th percentile

A

first quartile, Q1

83
Q

divides the bottom 50% of data from the top 50%; 50th percentile or the median

A

second quartile, Q2

84
Q

divides the bottom 75% of the data from the top 25%; 75th quartile

A

third quartile, Q3

85
Q

the range of the middle 50% of the observations in a data set; the difference between the third and first quartiles

A

interquartile range; IQR; IQR=Q3-Q1

86
Q

extreme observations

A

outliers

87
Q

serve as cutoff points for determining outliers

A

fences

88
Q

the measure of the likelihood of a random phenomenon or chance behavior occurring

A

probability

89
Q

short term results

A

outcomes

90
Q

any process with uncertain results that can be repeated

A

experiment

91
Q

the collection of all possible outcomes of a probability experiment

A

sample space, S

92
Q

any collection of outcomes from a probability experiment; consists of one outcome or more than one outcome

A

event, E

93
Q

lists the possible outcomes of a probability experiment and each outcome’s probability

A

probability model

94
Q

when the probability of an event is 0

A

impossible

95
Q

when the probability of an event is 1

A

certainty

96
Q

an event that has a low probability of occurring; less than 0.05 or 5%

A

unusual event

97
Q

when each outcome has the same probability of occurring

A

equally likely outcomes

MAT 158 (2 decks)

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