Biostatistics Basics

Question 1

What are the 2 types of variables?

Answer 1

Independent

Dependent

Question 2

Independent variables precede dependent variables in what?

Answer 2

Time

Question 3

What variable can be manipulated by the researcher?

Answer 3

Independent

Question 4

The treatment or intervention is what variable?

Answer 4

Independent

Question 5

The dependent variable depends on what?

Answer 5

Independent Variable

Question 6

What is the group from which a sample is drawn?

Answer 6

Population

Question 7

What is a subset of a population?

Answer 7

Sample

Question 8

What type of samples are representative of the source population?

Answer 8

Random Samples

Question 9

Random assignment is also known as?

Answer 9

Randomization

Question 10

What is a way to summarize data from a sample or a population?

Answer 10

Descriptive Statistics

Question 11

Descriptive statistics illustrate what of a set of data?

Answer 11

Shape
Central Tendency
Variability

Question 12

The shape of the data involves frequencies of what?

Answer 12

Values of observataions

Question 13

Central tendency means the location is where?

Answer 13

Middle of the data

Question 14

Variability refers to?

Answer 14

Spread

Dispersion

Question 15

What visually depict frequency distributions of continuous data?

Answer 15

Histograms

Question 16

What are used to depict categorical information?

Answer 16

Bar Charts

Question 17

What is the most common descriptive statistic?

Answer 17

Mean (average)

Question 18

What is the most frequently occurring value in a series?

Answer 18

Mode

Question 19

The value that divides a series of values in half when they are all listed in order is known as what?

Answer 19

Median

Question 20

What are the 4 levels of measurement?

Answer 20

N-Nominal (name/label)
O-Ordinal (ordered rank)
I-Interval (equal intervals)
R-Ratio (true zero)

Question 21

What are often symmetrical with most scores falling in the middle and fewer toward extremes?

Answer 21

Distributions

Question 22

Most biological data are symmetrically distributed and form what?

Answer 22

Normal Curve (bell-shaped curve)

Question 23

The area under a normal curve has what?

Answer 23

Normal Distribution

Question 24

What are some properties of a normal distribution?

Answer 24

Symmetric about it’s mean
Highest point is at mean
Height of curve decreases as one moves away from mean in either direction, never reaches zero.

Question 25

What does it mean when there is a skewed distribution?

Answer 25

Mean, median and mode are not equal and are in different positions.

Question 26

Skew is always toward the direction of which tail?

Answer 26

Longer Tail
+ = Right
- = Left

Question 27

What is a better estimate of the center of skewed distributions?

Answer 27

Median (central point of distribution)

Question 28

What is a measure of the variability of a set of data?

Answer 28

Standard Deviation

Question 29

The range of scores is referred to as?

Answer 29

Variability or Spread

Question 30

What is the number of standard deviations that a specific score is above or below the mean in a distribution?

Answer 30

Z-Scores

Question 31

The proportion of scores that are higher or lower than a specific z-score can be determined by referring to?

Answer 31

z-table