Biostatistics II

Question 1

variable also known as_____?

Answer 1

data

Question 2

any measurement that can have different values across individuals (e.g., height, weight, age, gender)

Answer 2

variable

Question 3

what are the roles of a variable?

Answer 3

predictor variable (Independent variable/Explanatory variable)
outcome variable(Dependent variable/Response variable)
confounding variable

Question 4

Intervention/treatment/therapy is an example of what type of variable?

Answer 4

predictor variable

Question 5

disease status is an example of what type of variable?

Answer 5

outcome variable

Question 6

demographic information like age and gender are examples of what type of variable?

Answer 6

confounding variable

Question 7

confounding variable is treated as what kind of variable in statistical modeling?

Answer 7

predictor variables

Question 8

data that are measured in a numerical scale and are expressed as numbers

Answer 8

Quantitative

Question 9

data that are described by words rather than numbers

Answer 9

Qualitative

Question 10

Systolic and diastolic blood pressure, height, weight

this is what type of data?

Answer 10

quantitative data

Question 11

open ended questions in surveys, eye color, Likert scale questions

this is what type of data?

Answer 11

qualitative data

Question 12

quantitative data has these two types of classification?

Answer 12

discrete or continuous

interval or ratio

Question 13

what are the categorical variables?

Answer 13

nominal
dichotomous
ordinal

Question 14

what type of categorical variable has the following characteristics?

Labels
No order information

Answer 14

Nominal

Question 15

what type of categorical variable has the following characteristics?

Only two possible labels
No order information

Answer 15

Dichotomous (a special case of Nominal)

Question 16

what type of categorical variable has the following characteristics?

Order (rank) information is maintained
Differences/ratios do not make sense

Answer 16

Ordinal

Question 17

blood type and occupation is what type of categorical variable?

Answer 17

nominal

Question 18

Test result: Positive/Negative

is what type of categorical variable?

Answer 18

Dichotomous (a special case of Nominal)

Question 19

Likert scale questions

Academic Tier is what type of categorical variable?

Answer 19

ordinal

Question 20

what are the two types of quantitative variables? what are their subsets?

Answer 20

discrete and continuous

interval and ratio

Question 21

this type of quantitative variable has the following characteristics?

Possible values are integers
Have acountablenumber of values

Answer 21

Discrete

Question 22

this type of quantitative variable has the following characteristics?

Can have any value in a range

Answer 22

Continuous

Question 23

Number of patients who were exposed to a risk factor
Number of patients who visited ER during last weekend

is an example of what type quantitative variable?

Answer 23

discrete

Question 24

Amount of time between meal being served and onset of gastro-intestinal symptoms
Infant mortality rate

is an example of what type quantitative variable?

Answer 24

continuous

Question 25

these subdivisions of discrete and continuous variables are these two types?

Answer 25

interval and ratio

Question 26

interval or ratio has the following characteristics that are either interval or ratio? No absolute zero exists Differences make sense but not ratios Only permits addition and subtraction

Answer 26

Interval

Question 27

interval or ratio has the following characteristics that are either interval or ratio? Zero represents a true absence Ratios make sense

Answer 27

Ratio

Question 28

this example: ``` Temperature in Celsius/Fahrenheit scale IQ score (most standardized tests scores in psychology) ``` is interval or ration?

Answer 28

interval

Question 29

this example: ``` Temperature in Kelvin scale Salary in $ Weight Risk and proportion is interval or ration? ```

Answer 29

ratio

Question 30

what should we consider when determining the type of a variable?

Answer 30

the research context and how it was measured Example: Age by nature is continuous and ratio, but it may be of other types: Age as ordinal: Age group 0-17, 18-60, 60+ Age as discrete: age at the last birthday, age on the day of medical school interview

Question 31

what are the tools used in descriptive statistics?

Answer 31

numerical measurements graphical tools

Question 32

what is the tool used from descriptive statistics derived from these examples? Measures of central tendency Measures of dispersion

Answer 32

numerical measurements Tools to choose depend on the type of variables

Question 33

what is the tool used from descriptive statistics derived from these examples? Frequency table Bar chart/Pie chart Histogram/Box plot Scatterplot

Answer 33

graphical tools Tools to choose depend on the type of variables

Question 34

what are the measures of central tendency?

Answer 34

mean median mode

Question 35

this measure of central tendency is an average of all values?

Answer 35

mean

Question 36

this measure of central tendency is the middle value of the ordered dataset?

Answer 36

median

Question 37

this measure of central tendency is the most commonly used value?

Answer 37

mode

Question 38

this measure of central tendency is used: Not robust to extreme values Makes most sense for quantitative variables

Answer 38

mean

Question 39

this measure of central tendency is used: Robust to extreme values Makes most sense for quantitative variables Can also be used for ordinal variables

Answer 39

median

Question 40

this measure of central tendency is used: Can be used to describe both categorical and quantitative variables Can have more than one modes

Answer 40

mode

Question 41

which of the following measures of central tendencies is applicable only to females?

Answer 41

mode

Question 42

which of the following measures of central tendencies is applicable to age?

Answer 42

mean and median

Question 43

what are the four measures of central tendencies?

Answer 43

variance standard deviation range interquartile range

Question 44

what is variance?

Answer 44

How close the values are to the mean

Question 45

what is standard deviation?

Answer 45

Square root of variance

Question 46

what is range?

Answer 46

Max value – min value

Question 47

what is interquartile range?

Answer 47

𝑄3-𝑄1

Question 48

these measures of dispersions are used: Not robust to extreme values Makes most sense for quantitative variables

Answer 48

variance standard deviation range

Question 49

this measure of dispersion is used: Robust to extreme values Makes most sense for quantitative variables

Answer 49

Interquartile Range

Question 50

A table listing the possible values for a variable, together with their (relative) frequencies.

Answer 50

frequency table

Question 51

this type of table is used when: for categorical variables measures number of times the observations fall into a certain category relative frequency=frequency/total

Answer 51

frequency table

Question 52

a circular diagram divided into segments, each representing a category of the variable.

Answer 52

Pie Chart

Question 53

a type of graph for presenting categorical variable in such a way that each observation can fall into one and only one category of the variable.

Answer 53

Bar Chart

Question 54

a graphical representation of the frequency distribution of a quantitative variable.

Answer 54

Histogram

Question 55

the significance of a histogram is to allow the inspection of the data for its underlying distribution, outliers, skewness, etc.

Answer 55

Histogram

Question 56

what are the following steps used to construct? Step 1: split the data into intervals, called bins. Step 2: use the table from step 1 to construct the histogram.

Answer 56

histogram

Question 57

this type of plot is used to present the distribution of a variable measured on a numerical scale (discrete or continuous). why?

Answer 57

Box plot It allows easy inspection of potential outliers and group comparisons (side-by-side box plot).

Question 58

the following is a guideline to use when it comes to potential outliers? Any point below the lower extreme/fence (𝑄_1−1.5𝐼𝑄𝑅) Any point above the upper extreme/fence (𝑄_3+1.5𝐼𝑄𝑅) IQR=Q3-Q1

Answer 58

Criteria for potential outliers (indicated by “∙” or “∗”)

Question 59

what is the significance of a box plot?

Answer 59

Side-by-side box plot allows visualization of group comparisons. its usually drawn out before working out a correlation or fitting a regression line

Question 60

pattern direction strength anomalies these are indications for a _____ (what type of plot)?

Answer 60

scatterplot

Question 61

this definition defines a variable of what to look for in a scatterplot? clusters of points or outliers like outliers and clusters

Answer 61

anomalies

Question 62

this type of anomaly consists of points that deviates from the overall pattern

Answer 62

outliers

Question 63

this type of anomaly consists of groups of points separated from one another

Answer 63

clusters

Question 64

how do we define the scatterplot trends?

Answer 64

strong, positive, liners no overall strong, quadratic clustered