Exam 1

Question 1

Scale Variable

Answer 1

A continuous variable where magnitude and order matter

Question 2

Ordinal Variable

Answer 2

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

Question 3

Nominal Variable

Answer 3

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

Question 4

Population

Answer 4

All members of interest

Question 5

Sample

Answer 5

a sub group of members of interest

Question 6

Population Mean Symbol

Answer 6

μ

Question 7

Variance of population symbol

Answer 7

σ^2

Question 8

Standard deviation of population symbol

Answer 8

σ

Question 9

Sample mean symbol

Answer 9

x bar

Question 10

Sample variance symbol

Answer 10

s^2

Question 11

Sample standard deviation symbol

Answer 11

s

Question 12

Is the word “data” plural or singular

Answer 12

plural

Question 13

Sampling Error

Answer 13

Difference between the sample and the actual population

Question 14

Which is better for skewed data: mean or median?

Answer 14

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

Question 15

Positive skew

Answer 15

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

Question 16

Negative Skew

Answer 16

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

Question 17

Which gives you more information: covariance or correlation?

Answer 17

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.

Question 18

Why do we use n-1 for sample calculations?

Answer 18

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

Question 19

What does the sum of squares show?

Answer 19

Shows the total spread around the mean

Question 20

0.0-0.2

Answer 20

Very Weak Correlation Size of r

Question 21

0.2-0.4

Answer 21

Weak correlation size of r

Question 22

0.4-0.6

Answer 22

moderate correlation size of r

Question 23

0.6-0.8

Answer 23

strong correlation size of r

Question 24

0.8-1.0

Answer 24

very strong correlation size of r

Question 25

What are the 4 assumptions of a pearson correlation?

Answer 25

linearly related, continuous scale variable, normal distribution, no significant outliers

Question 26

What does IQR tell us and why is this better than range?

Answer 26

IQR is the range between 25th-75th percentile. This is better than range because it trims out the bottom and top 25%

Question 27

Why do we square root the variance?

Answer 27

to get back to the original units

Question 28

How many scores are within +/-1 SD in a normal distribution?

Answer 28

2/3

Question 29

How many scores are within +/-2 SD in a noraml distribution

Answer 29

95%

Question 30

How many scores are within +/-3 SD in a normal distribution

Answer 30

99.7%

Question 31

What is a standardized distribution?

Answer 31

a predetermined standard deviation and mean

Question 32

Cross-sectional study

Answer 32

looking at data from a single point in time

Question 33

Randomized controlled trial

Answer 33

randomly assigning people to a group with a control group and a test group

Question 34

Case Report

Answer 34

Serve to convey information to others and to catalog new ideas and information. Doesn’t contain high quality evidence.

Question 35

Prospective cohort study

Answer 35

observational and following a group of people into the future

Question 36

Case Control

Answer 36

anytime you’re seeing matching.

Question 37

Meta analysis

Answer 37

collecting and reviewing all relevant papers