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Stats > exam 1 > Flashcards

exam 1 Flashcards

1
Q

how do you calculate z score

A

(value of int - mean) / SD

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2
Q

what are the types of variables?

A

Catagorial, Numerical, Nominal, Ordinal, Discrete, Continuous

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3
Q

what is a nominal variable?

A

Defined catagory with no specific order

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4
Q

Example of a nominal variable

A

Marital status, Political party, eye color

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5
Q

what is a ordinal variable

A

ordered catagories

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6
Q

ordinal variable examPLE

A

Freshman, sophmore, junior, senior

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6
Q

Population (N)

A

Contains all of the items or indivuduals of interest that you seek to study

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7
Q

Sample (n)

A

Contains only a portion of a population interest

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8
Q

Population parameter

A

summarizes the value of a specific variable for a population

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9
Q

sample statistic

A

summarizes the value of a specific variable for sample data

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10
Q

Probability sample

A

items in the
sample are chosen on the basis of known
probabilities.

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11
Q

which are probability samples

A

simple random, stratified, cluster, systematic

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12
Q

What type of samples are non probability

A

Judgement, Convenience

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13
Q

Simple random sample

A

Participants are randomly selected from a population

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14
Q

systematic

A

Method for selecting sample from a population in a randomized manner to minimize sampling error

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15
Q

Stratified sample

A

Divides population into two or more subgroups according to some common characteristics. A sample is taken from each group and is combined into one

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16
Q

Cluster sample

A

Population is divided into several clusters, each representing the population

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17
Q

Benefit of using Radom sample and systematic sample

A

simple to use

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18
Q

benefit of stratified sample

A

ensures respresentation of individuals across the entire population

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19
Q

cluster sample

A

more cost effective

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20
Q

convince sampling

A

individuals are selected based on only the fact that they are easy, inexpensive or convinent

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21
Q

Judgement sample

A

you get opinions of preselected experts in the subject matter

22
Q

Coverage error or selection bias

A

exists if some group are excluded from the frame and have no change of being selected

23
Q

nonresponse or bias error

A

people who do respond may be different from those who don’t respond

24
Q

sampling error

A

variation from sample to sample will always exist

25
Q

measurement error

A

due to weakness in question design and / or respondent error

26
Q

How is the Pareto chart organized?

A

The “Vital Few” (most influential) are the first on the X axis

27
Q

what is the stem and leaf display

A

organized data into groups (Stems) so that the values within each group (Leaves) can branch out to the right on each row

28
Q

what is the geometric mean

A

Rate of change of a variable over time

29
Q

what does the measure of variation give

A

Information on the spread of variability or dispersion of the data values

30
Q

what is the rule of thumb for z score

A

Greater then 3 or less then -3 are outliers

31
Q

what is the five number summary

A

the 5 numbers that help describe the center, spread and shape of data

32
Q

what is included in the 5 number summary

A

Min, Q1, Median, Q3, Max

33
Q

Left skewed

A

Mean< Median

34
Q

Symmetric

A

Mean = Median

35
Q

Right-Skewed

A

Median < Mean

36
Q

Empiracle rule

A

approximates the variation of data in a symmetric bell distributin

37
Q

In the empriacle rule how much of the data is within 1 standard deviation of the mean

A

68%

38
Q

In the empriacle rule how much of the data lies within 2 standard deviations of the mean

A

95%

39
Q

In the empriacle rule how much of the date lies within three standard deviations of the mean

A

99.7%

40
Q

When do you use chebyshevs rule

A

to find the values that fall within k of the mean

41
Q

Cov(x,y)>0

A

X and Y move in the same direction

42
Q

Cov(x,y) < 0

A

X and Y move in opposite directions

43
Q

Cov(x,y) = 0

A

X and Y are independent

44
Q

Can you determine the strength of relationship from COV

A

No

45
Q

coeffienct of correlation

A

measures the relative strength of the linear relationship between two numerical variables

46
Q

Priori probability

A

Based on prior knowledge of the process

47
Q

Empiracle probability

A

Based on specific date

48
Q

Subjective probability

A

Based on a combination of general date, personal opinion, and analysis of a particular situation

49
Q

Continuous

A

Measurment

50
Q

Discrete

A

Counting (EX: number of students)

51
Q

What is a distinct clue it is Pareto

A

WIll say “Trival Many” and is catagorial

52
Q

when is the only time you can use empiracle rule

A

If data is bell shaped

53
Q

Subjective

A

Analysis of a subject

Stats (5 decks)

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