4. Basic Statistics II

Question 1

measures of dispersion versus measure of central tendency?

Answer 1

measure of central tendency = describe the typical or central value in a distribution (mean median mode)

measures of dispersion = describe the spread of the data (range standard deviation)

Question 2

standard deviation

Answer 2

measures the amount of variation or dispersion from the average

low sigma (sign for SD) = data points tend to be close to mean

large sigma (sign for SD) = data points spread out

Question 3

variance

Answer 3

directly related to standard deviation

it is the square of SD

sigma squared

Question 4

nominal data

Answer 4

nominal referes to categorically discrete data such as name

Norminal = name

Question 5

ordinal data

Answer 5

data that has a discrete ranking

grades

ordinal = order

Question 6

interval data

Answer 6

numerical data that is measured along a scale

example is temp in F

Question 7

ratio data

Answer 7

ratio data is interval data with a natural zero point
no negative numbers

Question 8

why does data type matter?

Answer 8

cannot add or subtract nominal data or ordinal data

Question 9

rank the measurements from less detailed to more detailed

Answer 9

norminal
ordinal
metric

Question 10

alternate vs null hypothesis

Answer 10

alternate hypothesis = statement that there is a difference between two events

null hypothesis = statement that there is no difference between two events

Question 11

statistical significance

Answer 11

statistical significance is the probability of rejecting the null hypothesis due to chance alone

expressed as P value

Smaller the P value the less likely it is that the results are due to chance and more likely the results are true

Question 12

P-value

Answer 12

smaller than 0.05 favored the alternate hypothesis

large than 0.05 favored the null hypothesis

Question 13

statistical significance chart

Answer 13

Question 14

statistical significance and null hypothesis

Answer 14

if the sample data are consistent with the null hypothesis then we fail to reject the null hypothesis

if the sample data are inconsistent with the null hypothesis then reject the null hypothesis

Question 15

only two options of statistical analysis

Answer 15

fail to reject the null hypothesis

reject the null hypothesis

Question 16

relationship of statistical and clinical significance

Answer 16

statistical significance does not equate to clinical significance

Question 17

what is clinical significance

Answer 17

the practical importance of a treatment effect = whether it has a real genuine palpable noticeable effect on daily life

Question 18

confounding factors

Answer 18

confounding factors are additional variables that could influence results that are not considered in the subject population selection

unknown bias

Question 19

what are the properties of a confounder

Answer 19

exposure is associated with the confounder

confounder is an independent risk factor for the disease

confounder is not in casual pathway