Biostatistics

Question 1

Independent Variable

Answer 1

Stimuli that researchers
manipulate to create
effect

Question 2

Descriptive Statistics

Answer 2

Refers to the differmethods
 applied
 summarize and present din a form to make them eato analyze and interpretusing methods of:
 • Tabulation
 • graphical representation
• summary measures

Question 3

Inferential Statistics

Answer 3

Methods involved in order t make generalizations and
 conclusions about a target
 population, based on result
 from a sample, includes:
 • estimation of parameters
 • testing of hypothesis

Question 4

TYPES OF DATA

Answer 4

Quantitative

Qualitative

Question 5

Nominal

Answer 5

Naming or categoric variables that are not based
on measurement scales or rank order.
• # or symbols are assigned. Lowest form of
variable: (e.g., Gender, Color, Province, occupation,skin color and blood group)
• Dichotomous (binary)- which has only two
levels (e.g., Yes or No, Normal and Abnormal, Male
and Female)

Question 6

Ordinal

Answer 6

• Arranged in rank ordered categories
• (E.g., Social class, Likert scale, Satisfactory scale,
agree to disagree, murmur range, level of edema)

Question 7

. ACCURACY/ACCURATE

Answer 7

o The closeness of a measured orvalue.

o Trueness of test measurements

Question 8

PRECISION/PRECISE

Answer 8

how close measurements of the same item are to each other

Question 9

Sensitivity

Answer 9

is the test’s ability to correctly designate a subject

with the disease as positive

Question 10

Specificity

Answer 10

Is the test’s ability to correctly designate a subject

without the disease as negative

Question 11

Positive Predictive Value

Answer 11

o (PPV) is the probability that a subject with a positive

(abnormal) test actually has the disease

Question 12

Negative Predictive Value

Answer 12

o (NPV) is the post-test probability that the subject has no disease given a negative test result

Question 13

Likelihood ratio

Answer 13

It is defined as the probability of a subject who has the disease testing positive divided by the probability of a subject who does not have the disease testing positive

Question 14

SELF-SELECTION BIAS

Answer 14

o people presenting for screening tend to be healthier leading to
false sense of better outcomes

Question 15

LEAD TIME BIAS

Answer 15

o refers to the phenomenon where early diagnosis of a disease
falsely makes it look like people are surviving longer. This
occurs most frequently in the context of screening.

Question 16

LENGTH BIAS

Answer 16

o refers to the fact that screening is more likely to pick up slower-growing, less aggressive cancers, which can exist in the body longer than fast-growing cancers before symptoms develop

Question 17

OVER-DIAGNOSIS BIAS

Answer 17

o An extreme example of length bias
o aggressive search for abnormalities might actually lead to
harm and great cost without reaping any benefits

Question 18

STRATIFIED

SAMPLING

Answer 18

• Sampling method where we divide the
 population
 into
 nonoverlapping
  subpopulations or strata, and then select
  one sample from each stratum
 • The sample consist of all the samples in the
different strata

Question 19

SYSTEMATIC
SAMPLING
DESIGN

Answer 19

• Selection of the first element is at random
and selection of the other elements is
subsequently taking every k
• Sampling interval is represented by k
• kth element of the population is chosen
(k=N/n, where N is the total population, and
n is the sample size needed

Question 20

CLUSTER

SAMPLING

Answer 20

• The population is first divided into sampling
units called clusters
A sample of clusters is selected
• Every element found in each cluster is
included in the study

Question 21

MULTISTAGE
SAMPLING
DESIGN

Answer 21

• There is hierarchical configuration of
sampling units and we select sample of
these units in stages
 • The population is 1st divided into a set of
primary or first stage sampling units
• Each primary sampling unit included in the
sample is further subdivided into
secondary or second stage sampling
units, from which a sample will again be
taken.

Question 22

MEAN,

Answer 22

Most commonmeasure
 of
central
 tendency;
 “average”

Question 23

MEDIAN,

Answer 23

• The value that falls
  in the middle
  position when the
  observations are
  ranked in order
  from the smallest
  to the largest.
  • If
 number
 of
  observations
 is
  odd, the median is
  the
 middle
  number
  • If it is even, the
  median is the
  average of the 2
  middle numbers.
  • Useful on skewed
  data
 • For ordinal or
 numeric data if
 skewed

Question 24

&

MODE

Answer 24

•  The value that
 occurs with the
 greatest
  frequency in a
 set
 of
 observations
  • Used in public
 health statistics
 (top
 10
 mortality and
 morbidity)
 • For
 bimodal
 distribution

Question 25

``` TYPE I (Α) ERROR LEVEL OF SIGNIFICANCE (α) ```

Answer 25

``` Error of rejecting the null hypothesis when it is really true Declaring a difference when none exists. Similar to false positive test ```

Question 26

``` TYPE II (Β) ERROR LEVEL OF SIGNIFICANCE (α) ```

Answer 26

``` Error of NOT rejecting the null hypothesis when it is actually false Failing to declare a difference that does exist. Similar to false negative test ```

Question 27

Rejecting or Accepting a Hypothesis Low P p

Answer 27

``` Value of sample results are far from the population parameters Unlikely events REJECT HO ```

Question 28

High P | p>α

Answer 28

``` Value of sample results are close to population parameters Likely events DO NOT REJECT H O ```

Question 29

. EXPANSIVE

Answer 29

used to describe populations that are young and growing characterized by their typical ‘pyramid’ shape has a broad base and narrow top show a larger percentage of the population in the younger age cohorts typically representative of developing nations, whose populations often have high fertility rates and lower than average life expectancies

Question 30

CONSTRICTIVE

Answer 30

used to describe populations that are elderly and shrinking often look like beehives and typically have an inverted shape with the graph tapering in at the bottom have smaller percentages of people in the younger age cohorts and are typically characteristic of countries with higher levels of social and economic development Base that is narrower than middle of the pyramid, usually the result of a recent rapid decline in fertility

Question 31

STATIONARY

Answer 31

• Narrow base and a roughly equal numbers in each age group, tapering off at the older ages, indicating a moderate proportion of children and a slow or zero rate of growth • used to describe populations that are not growing • characterized by their rectangular shape, displaying somewhat equal percentages across age cohorts that taper off toward the top • characteristic of developed nations, where birth rates are low and overall quality of life is high

Question 32

SWAROOP’S INDEX:

Answer 32

Number of deaths among those 50 years and older in a calendar year

Question 33

CASE FATALITY RATE:

Answer 33

Measures killing power of disease High CFR means a more fatal disease. A higher CFR is expected from a hospital statistics than from the community

Question 34

Case-control (often | called retrospective)

Answer 34

• Define diseased subjects (cases) and non- diseased subjects (controls); compare proportion of cases with exposure (risk factor) with proportion of controls with exposure (risk factor)

Question 35

Cohort (usually prospective; occasionally retrospective)

Answer 35

``` • In study population, define exposed group (with risk factor) and nonexposed group (without risk factor) • Over time, compare proportion of exposed group with outcome (disease) with proportion of nonexposed group with outcome (disease) ```

Question 36

Cross-sectional

Answer 36

``` • In study population, concurrently measure outcome (disease) and risk factor • Compare proportion of diseased group with risk factor with proportion of non- diseased group with risk factor ```

Question 37

Clinical trial | (experiment)

Answer 37

``` • In study population, assign (randomly) subjects to receive treatment or receive no treatment • Compare rate of outcome (e.g., disease cure) between treatment and nontreatment groups ```

Question 38

Meta-analysis

Answer 38

• Collates data from multiple independent studies to maximize precision and power in testing for statistical significance