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MA223—Elementary Probability & Statistics > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

parameter

A

characteristic of a population

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2
Q

statistic

A

characteristic of a sample

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3
Q

descriptive statistics

A

collection, organization, summarization, presentation of data

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4
Q

inferential statistics

A

generalizing from samples to populations, estimatinons, hypothesis testing, determining relationships, making predictions

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5
Q

inferential stats based on _________

A

probability

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6
Q

qualitative

A

variables can be placed into distinct categories according to some characteristic

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7
Q

quantitative

A

variables are numerical and can be ordered/ranked

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8
Q

2 types of quantitative data

A

discrete
continuous

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9
Q

nominal data

A

mutually exclusive, exhausting categories which cannot be ordered/ranked

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10
Q

ordinal data

A

categories with no precise differences which can be ranked

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11
Q

interval data

A

data is ranked and precise differences exist, but there is no meaningful 0, so ratios are meaningless

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12
Q

ratio data

A

data is ranked and precise differences exist, and ratios are meaningful because there is a meaningful 0

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13
Q

systematic sampling

A

every kth subject

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14
Q

stratified sampling

A

divide population into layers and sample from each

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15
Q

cluster sampling

A

sample from existing groups

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16
Q

sample population

A

portion of target population accessible for sampling from

we take the sample from the sample pop.

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17
Q

problem with simple random sampling

A

can give a nonrepresentative sample

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18
Q

2 stages of cluster sampling

A
  1. randomly select clusters
  2. from clusters, randomly select subjects
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19
Q

3 nonsampling errors

A

nonresponse
response error
selection bias

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20
Q

frequency distribution

A

organization of raw data in table form, using classes as frequencies

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21
Q

categorical distribution is for … data

A

nominal

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22
Q

grouped distribution is for…. data

A

data with a large range requiring classes several units in width

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23
Q

ungrouped distribution is for …. data

A

numerical data with a small range

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24
Q

steps for constructing a frequency distribution

A
  1. make categories
  2. count/tally
  3. find frequency
  4. find relative frequency
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25
Q

relative frequency =

A

frequency / total

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26
Q

all categorical data can be represented by a ….

A

bar graph

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27
Q

class boundaries

A

used to separate classes

**

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28
Q

class rules

A
  1. limits should have same decimal place value as data
  2. boundaries should have one additional place and end in 5
  3. width must be the same for every class
  4. width should be an odd number
  5. there should be 5-20 classes
  6. classes should be exhaustive, mututally exclusive, continuous
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29
Q

class width =

A

range / # of classes

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30
Q

find class midpoint by…

A

taking avg of 2 class boundaries

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31
Q

steps to construct a grouped distribution

A
  1. determine classes and class width
  2. sort data into classes
  3. find frequencies
  4. find cumulative frequencies
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32
Q

uses class bounderies (x ax) and frequencies (y ax) to give a “bar graph” with bars that cannot be rearranged

A

histogram

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33
Q

uses lines to connect points plotted at the midpoint of each class

A

polygon

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34
Q

a polygon is anchored…

A

at the x ax before and after the data

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35
Q

uses lines that connect points plotted at the cumulative frequency of each class

A

ogive

36
Q

an ogive has…. on the x ax

A

upper class boundaries

37
Q

graph using proportions

A

relative frequency graph

38
Q

used for categorical variables; bars arranged highest to lowest

A

Pareto chart

39
Q

represents data that occur over a period of time

A

time series graph

40
Q
A

bell shape

41
Q
A

uniform shape

42
Q
A

right skewed shape

43
Q
A

left skewed shape

44
Q
A

bimodal shape

45
Q

weighted mean formula

A
46
Q

table for grouped data’s mean

mean formula

A

A: class
B: frequency, f
C: midpoint, Xm
D: f(Xm)

mean = ΣD/n

47
Q

mean for grouped data is ……

A

approximate

48
Q

find median for an odd n

A

(n + 1)/2

49
Q

find median for an even n

A

find mean of n/2 and (n+1)/2

50
Q

measures of central tendency for right skew

A

mode < median < mean

51
Q

measures of central tendency for left skew

A

mean < median < mode

52
Q

variance

A

average deviation squared

53
Q

s^2

A

sample variance

54
Q

standard deviation

A

square root of variance

55
Q

variance and std dev used to determine …… of a variable

A

consistency

56
Q

steps to find std dev

A
  1. find mean
  2. find deviation of each value: x - mean
  3. square each deviation
  4. find sum of the squares
  5. divide by N or n-1
57
Q

standard deviation =

A
58
Q

unbiased estimate is …….

and is used to…

A

n - 1

compensate for the underestimation of population variance given by n alone

59
Q

coefficient of variation =

A

100 (s/x)

60
Q

range rule of thumb

A

s = R/4

61
Q

range rule of thumb works when…

A

data is unimodal and approximately symmetric

62
Q

chebyshev’s formula

A
63
Q

chebyshev’s theorem states…

A

proportion of values from a data set that fall within k standard deviations of the mean will be at least 1 - 1/k^2 where k > 1

64
Q

% for k = 2

A

75%

65
Q

% for k = 3

A

88.9%

66
Q

% for k = 4

A

93.8%

67
Q

empirical rule applies to ….. distributions

A

normal

68
Q

empirical rule
1 s:
2 s:
3 s:

A

1 s: 68% inside, 16% on either side
2 s: 95% inside, 2.5% on either side
3 s: 99.7% inside, 0.15% on either side

69
Q

standard/z score definition

A

unitless measure expressing how many s above or below the mean an observation is

70
Q

z score used when…

A

raw data can’t be directly compared

71
Q

z =

A
72
Q

percentiles used in…

A

education, healthcare

73
Q

percentile indicates…

A

position of an individual in a group

74
Q

P is… such that….

A

P is an integer between 1 and 99 such that the Pth percentile is a value where P% of the data is less than or equal to the value

75
Q

percentile =

A

[(values below x) + 0.5 / total # of values ]100

76
Q

the cth value corresponds to the Pth percentile formula

A

c = nP/100

77
Q

if c is a decimal…

A

round up

78
Q

if c is a whole….

A

take avg of cth and (c+1)th values

79
Q

Q1 = __th percentile

A

25th

80
Q

Q3 = __th percentile

A

75th

81
Q

steps to find quartiles

A
  1. arrange data in order
  2. find median, Q2
  3. Q1 = median of first half
  4. Q3 = median of second half
82
Q

5-number summary

A

min
max
Q1
median
Q3

83
Q

hypothesis testing

A

decision-making process for evaluating claims about a population, based on information from samples

84
Q

how to find outlier interval

A

Q1 - IQR(1.5)

and

Q3 + IQR(1.5)

85
Q

5 number summary

A

min
Q1
median
Q3
max

MA223—Elementary Probability & Statistics (3 decks)

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