Application of biostatistics definitions

Question 1

descriptive statistics

Answer 1

analyses that help describe, show, summarize our data

Question 2

inferential statistics

Answer 2

analyses that allow us make conclusions about relationship btwn indpndnt and dpndnt variables or generalize our samples findings to the population

Question 3

Types of Data

Answer 3

discrete –> nominal and ordinal

continuous –> interval and ratio

Question 4

mean

Answer 4

average

Question 5

median

Answer 5

middle value in range

Question 6

mode

Answer 6

most frequent value observed

Question 7

perfect distribution - mean median mode

Answer 7

all identical

Question 8

symmetrical distribution

Answer 8

mean mode median in middle

Question 9

positive skew

Answer 9

maxima tends left

L–>R
mode median mean

Question 10

negative skew

Answer 10

absolute maxima tends right

L —> R
mean, median, mode

Question 11

null hypothesis

Answer 11

typically that independent variable has no effect on dependent variable

in study wanting to see if two options are equivalent
- no there is a difference bteween option A and B

Question 12

alternative hypothesis

Answer 12

independent variable has significant effect on dependent variable

Question 13

type one error

Answer 13

null is true and you reject

Question 14

type II error

Answer 14

null is false and you accept

Question 15

statistical power

Answer 15

likelihood that a study will detect an effect when there is an effect there to be detected

power = 1 - beta ; beta = p(TypeII)

Question 16

primary outcome

Answer 16

outcome that will answer the primary (most important) question

ex. whether a treatment is better at preventing disease- related death than the standard therapy

sample size of trial is calculated based on change expect see in this outcome

Question 17

secondary outcome

Answer 17

other relevant outcomes about the same study but less importance

ex. wheter also a reduction in disease measures other than death, or whether new treatmnet reduces overall cost

hypothesis generating only

Question 18

composite outcome

Answer 18

other relevant outcomes are combined to form a single primary outcome

Question 19

chi square test

Answer 19

when categorical independent and independent variable

Question 20

t-test and ANOVA

Answer 20

when categorical independent and continuous dependent

Question 21

regression test

Answer 21

continuous independent and dependent variable

Question 22

paired t-test

Answer 22

both measures come from the same subject

-ex comparing means obtained in a cross over study

Question 23

unpaired t-test

Answer 23

measures come from diff subjects

Question 24

ANOVA

Answer 24

used when more than 2 independent variables

-like series of t-tests

Question 25

efficacy

Answer 25

measure of capacity of a treatment to produce the desired effect in a controlled environment, such as in randomized controlled trial

Question 26

effectiveness

Answer 26

actual effect of treatment in practice

Question 27

accuracy

Answer 27

how close measurement is to true/accepted value

Question 28

precise

Answer 28

how close measurements of same item are to eachother

Question 29

validity

Answer 29

does the variable reported actually measure an outcome of interest

Question 30

sensitivity

Answer 30

ability of a test to correctly ID those patients with the disease
- sensitive test has low rate of false negatives

Question 31

specificity

Answer 31

ability of test to correctly ID those patients without the disease
-low rate of false positive

Question 32

statistical significance

Answer 32

difference btwn two interventions resulting in p<0.05

Question 33

clinical significance

Answer 33

difference bwtn two interventions that is meaningful to the patient and their outcomes