Exam 3 Material Flashcards

1
Q

Null hypothesis (Ho)

A

A research perspective in which there is no true difference between the comparison groups

Accepted - there is NO difference
Rejected - there IS a difference

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2
Q

Nominal data

A

Dichotomous/binary; non-ranked; named categories

No magnitude/order
No consistency of scale
No rational/absolute zero

Ex. Male vs. Female / colors / ethnicities

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3
Q

Ordinal data

A

Ordered, rank-able categories

HAS magnitude/order
No consistency of scale
No rational/absolute zero

Ex: satisfaction surveys / mood levels / pain scale (though some researches see it as interval data)

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4
Q

Interval data

A

HAS magnitude/order
HAS consistency of scale
No rational/absolute zero (can have negative values)

Ex: temperature / height / specific number on a known scale

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5
Q

What is the difference between interval and ratio data?

A

Interval data has an arbitrary 0 - can have (-) numbers

Ratio data has an absolute 0 - cannot have (-) numbers; “0” represents the absence of a measured value; typical of physiological measurements like BP, height, etc.

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6
Q

Discrete vs. Continuous data sets

A

Discrete = Nominal and Ordinal data

Continuous = Interval/ratio data

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7
Q

Descriptive statistics

A

Non-comparative, simple description of various elements of a study’s data

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8
Q

Mean vs. Median vs. Mode

A

MEAN = average

MEDIAN = the middle of a data set

MODE = most frequent number in a data set

Ex. 1, 1, 1, 2, 4, 5, 5, 8, 8
Mean = (1+1+1+2+4+5+5+8+8)/9 = 3.88
Median = 4
Mode = 1

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9
Q

What do outliers affect?

A

The mean/average of a data set

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10
Q

Interquartile range

A

IQR = Q3 - Q1

The middle 50% of a range of data

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11
Q

Variance

A

The average of the squared differences between each individual measurement value and the groups’ mean

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12
Q

Standard deviation

A

Square root of the variance

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13
Q

Normal distribution

A

When the mean of a data set is equal (or nearly equal) to the median, such that there is equal dispersion of a curve’s tails on either side of the mean

Skewness = 0
Kurtosis = 0
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14
Q

What tests are useful for normally distributed data?

A

Parametric tests

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15
Q

Positive skew

A

When the mean > median for a data set

Results in a curve shifted to the LEFT (tail point to the right)

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16
Q

Negative skew

A

When the mean < median in a data set

Results in a curve shifted to the RIGHT (tail points to the left)

17
Q

Given: mean = 15 / median = 3 / mode = 0

Is the data skewed? How do you know?

A

Yes: Because the mean > median, the data is positively skewed

18
Q

Skewness

A

A measure of asymmetry of distribution

Normal distribution is symmetrical (skewness=0)

19
Q

Kurtosis

A

A measure of the extent to which observations cluster around the mean:

(+) kurtosis indicates more cluster
(-) kurtosis indicates less cluster

Normal distribution “clusters” evenly about the mean (kurtosis=0)