Exam 1 Flashcards

1
Q

Scale Variable

A

A continuous variable where magnitude and order matter

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2
Q

Ordinal Variable

A

a categorical variable where the order matters but not the magnitude (ex. 1 is below average, 2 is average, and 3 is above average)

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3
Q

Nominal Variable

A

A categorical variable where order and magnitude don’t matter (ex. 1 is female, 2 is male)

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4
Q

Population

A

All members of interest

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5
Q

Sample

A

a sub group of members of interest

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6
Q

Population Mean Symbol

A

μ

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7
Q

Variance of population symbol

A

σ^2

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8
Q

Standard deviation of population symbol

A

σ

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9
Q

Sample mean symbol

A

x bar

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10
Q

Sample variance symbol

A

s^2

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11
Q

Sample standard deviation symbol

A

s

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12
Q

Is the word “data” plural or singular

A

plural

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13
Q

Sampling Error

A

Difference between the sample and the actual population

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14
Q

Which is better for skewed data: mean or median?

A

Median, because each data point has the same weight as another data point and is less impacted by outliers.

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15
Q

Positive skew

A

Hump is on the left and the tail is being pulled right

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16
Q

Negative Skew

A

Hump is on the right and the tail is being pulled left

17
Q

Which gives you more information: covariance or correlation?

A

Both tell you what direction the variables go (together or opposite) but correlation gives you the magnitude of the direction they move together or apart in.

18
Q

Why do we use n-1 for sample calculations?

A

Accounts for the fact that there is some bias in the sample

19
Q

What does the sum of squares show?

A

Shows the total spread around the mean

20
Q

0.0-0.2

A

Very Weak Correlation Size of r

21
Q

0.2-0.4

A

Weak correlation size of r

22
Q

0.4-0.6

A

moderate correlation size of r

23
Q

0.6-0.8

A

strong correlation size of r

24
Q

0.8-1.0

A

very strong correlation size of r

25
What are the 4 assumptions of a pearson correlation?
linearly related, continuous scale variable, normal distribution, no significant outliers
26
What does IQR tell us and why is this better than range?
IQR is the range between 25th-75th percentile. This is better than range because it trims out the bottom and top 25%
27
Why do we square root the variance?
to get back to the original units
28
How many scores are within +/-1 SD in a normal distribution?
2/3
29
How many scores are within +/-2 SD in a noraml distribution
95%
30
How many scores are within +/-3 SD in a normal distribution
99.7%
31
What is a standardized distribution?
a predetermined standard deviation and mean
32
Cross-sectional study
looking at data from a single point in time
33
Randomized controlled trial
randomly assigning people to a group with a control group and a test group
34
Case Report
Serve to convey information to others and to catalog new ideas and information. Doesn't contain high quality evidence.
35
Prospective cohort study
observational and following a group of people into the future
36
Case Control
anytime you're seeing matching.
37
Meta analysis
collecting and reviewing all relevant papers