Basic Statistics II (4) - End E1 Flashcards

1
Q

What are measures of central tendency?

A

describe the typical or central value in a distribution
- mean, median, mode

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2
Q

What are measures of dispersion?

A

describe the spread of data
- range, standard deviation, variance

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3
Q

What is standard deviation?

A

measures the amount of variation or dispersion from the average

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4
Q

What does a high standard deviation mean?

A

indicates that the data points are spread out over a large range of values

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5
Q

What does a low standard deviation mean?

A

the data points tend to be very close to the mean (also called expected value)

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6
Q

What is variance?

A

directly related to standard deviation

the square of it - sigma squared

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7
Q

Would this have a high or low variance?

A

low

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8
Q

What is categorical data?

A

nominal
ordinal

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9
Q

What is numerical data?

A

interval
ratio

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10
Q

What is nominal data?

A

refers to categorically discrete data such as name

part of categorical data

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11
Q

What is ordinal data?

A

data that has a discrete ranking

ex. freshman, sophomore, etc

order like ordinal

type of categorical data

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12
Q

What is interval data?

A

numerical data that is measured along a scale
each point is at equal distance from one another

type of numerical data

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13
Q

T/F: Intervals can have negative values 0 is arbitrary

A

TRUE

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14
Q

What is ratio data?

A

interval data with a natural data point

type of numerical data

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15
Q

What is required in ratio data?

A

NO negative numbers

0 is a true zero

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16
Q

Can you add and subtract types of categorical (ordinal, nominal) data?

A

NO

17
Q

What is an alternative hypothesis?

A

statement that there is a difference between 2 events (treatments, tests, etc)

18
Q

What is the null hypothesis?

A

statement that there is no difference between two events

19
Q

What is statistical significance?

A

the probability of rejecting the null hypothesis due to chance alone (given that the null hypothesis is true)

usually expressed as a p value

20
Q

Regarding accepting and rejecting hypotheses, what can we NOT do?

A

accept the alternative hypothesis
accept the null hypothesis
reject the alternative hypothesis

21
Q

Statistical significance does not necessarily equate to ______

A

clinical significance

22
Q

What is clinical significance?

A

the practical importance of a treatment effect - whether it has a real genuine, palpable, noticeable effect on daily life

23
Q

What are confounding factors?

A

additional variable that could influence results that are not considered in the subject population selection (unknown bias)

24
Q

What are potential confounders?

A

age
IQ
prior coursework
gender
outside work
marital status

25
Q

What are properties of a confounder?

A

exposure
independent of risk factor of disease
not in casual pathway