# Biostats/Epi Week 3 Flashcards

You are developing a new screen for heart disease which is found to correlate (r=0.7) with the “gold standard” blood test for cardiac enzymes. This is an indication of:

convergent validity

Variable

Anything that can take on a different quality or quantity.

Data distribution

listing of values associated with a particular variable in a collection of data

Frequency distribution

table or graph that indicates how many times a value appears in a data set.

Nominal level of measurement

simplest level of measurement; based on categories that are mutually exclusive and collectively exhaustive.

Ordinal level of measurement

level of measurement that presumes order (i.e. greater than, less than).

Interval level of measurement

measurement based on a scale of equal intervals (a.k.a. ratio level of measurement)

Population (or universe)

all possible criteria cases; complete total cases possible

Sample

Portion of the population collected; from the sample conclusions are drawn about the population

Parameter

characteristic of a population

Statistic

characteristic of a sample

Descriptive Statistics

used to summarize or describe data distributions

Inferential Statistics

used to make statements about a population

You are studying a new screening test. There are 40 people who do not have a disease and 20 test negative for the disease with your new screen. Your new screen’s specificity is:

50%

Your sample is normally distributed with a mean age of 57. The standard deviation in this sample is 5 years. The 2000 census shows your sample is older than a randomly selected national sample. You would expect 68% of your subjects to be:

Between the ages of 52 and 62