Biostatistics

Question 1

Discrete variable

Answer 1

Can take only a limited number of values within a given range

Question 1

Nominal

Answer 1

Discrete Variable that is classified into groups in an unordered manner

Question 2

What kind of variable is “disease presence [yes or no]”

Answer 2

Nominal variable

Question 3

Ordinal variable

Answer 3

ranked in a specific order but with no consistent magnitude of difference between rankes

Question 4

What kind of variable is “NYHA functional class”

Answer 4

Ordinal variable

Question 5

What is the most common error type in data with discrete variables?

Answer 5

Measure of central tendency- in most cases means and standard deviations should not be reported with ordinal data

Question 6

Continuous variables

Answer 6

can take on any value within a given range

Question 7

What kind of variable is interval

Answer 7

Continuous variable with data ranked in a specific order with a consistent change in magnitude between variables

Question 8

What kind of data is degrees Fahrenheit?

Answer 8

Interval variable

Question 9

What kind of variable is ratio data?

Answer 9

Like “interval” but with absolute zero

Question 10

What kind of data is heart rate or blood pressure

Answer 10

Ratio (continuous variable)

Question 11

Arithmetic mean (average)
-Definition
-What data should be used
-Weaknesses

Answer 11

-Sum of all values divided by the total number of values
-continuous and normally distributed data
-very sensitive to outliers and tend toward the tail

Question 12

Median
-Definition
-What data should be used
-weaknesses

Answer 12

-midpoint of the values when placed in order from highest to lowest
-ordinal or continuous data
-insensitive to outliers

Question 13

Mode
-Definition
-What data should be used
-weaknesses

Answer 13

-Most common value in a distribution
-nominal, ordinal, or continuous data
-does not describe meaningful distributions with large range of values, each of which occurs infrequently

Question 14

Standard deviation
-Definition
-How to find (mathmatically)

Answer 14

-measure of variability about the mean (spread of data)
-square root of the variance (average squared difference of each obs from the mean)

Question 15

Range
-Definition
-Weakness

Answer 15

-Difference between the smallest and largest values in a data set
-Very sensitive to outliers

Question 16

Percentiles
-Definition
-Example

Answer 16

-The point (value) in a distribution in which a value is larger than some percentage of the other values in the sample. Can be calculated by ranking all data in a data set
-The 75th percentile lies at a point at which 75% of the other values are smaller

Question 17

Inferential Statistics
-Definition

Answer 17

Conclusions or generalizations made about a population (large group) from the study of a sample of that population

Answer 18

the wider the CI –> the more likely it is to encompass the true population

Question 19

What test will compare the mean of the study sample with the population mean (or two independent samples)?

Answer 19

Student-t test

Question 20

What kind of test will compare matched samples

Answer 20

paired student t-test

Question 21

What does ANOVA stand for?

Answer 21

analysis of variance

Question 22

What kind of test can be used to compare more han two groups?

Answer 22

ANOVA

Question 23

What does ANCOVA stand for?

Answer 23

Analysis of covariance

Question 24

What kind of test explains the influence of one variable on another while statistically controlling for other variables?

Answer 24

ANCOVA

Question 25

What kind of tests should be used when you dont have discrete data or data is not normally distributed?

Answer 25

Nonparametric tests