Chapter 2: Biostats (continued) Flashcards
What are the types of scales we use to convert the world into numbers?
nominal, ordinal, interval, ratio scales
Another name for the nominal scale?
categorical
What is an ordinal scale?
When groups are in sequence (i.e rank order)
What is interval scale?
Uses a scale graded in equal increments (i.e quantity, mean, and AD) (i.e. height, weight)
What is a ratio scale?
interval + true zero point (i.e. T measured in degrees Kelvin)
What is a correlation coefficient?
indicates the degree to which 2 measures are related not why they are related
What does a pearson correlation compare?
2 interval level variables
What does a spearman correlation compare?
compares 2 ordinal level variables
What is the meaning of a + correlation variable?
2 variables go together in the same direction (e.g. MCAT scores have a positive correlation with medical school grades)
Chi square compares what types of data?
nominal data only
It tests to see whether 2 nominal variables are independent (i.e in order to test the effiacy of a new drug, compare the number of recovered patients give drug)
t-test is used for assessing what types of information?
combination of nominal and interval data
compares the means of 2 groups from a single nominal variable, using means from an interval variable to see whether the groups are different
A negative correlation coefficient value has what significance?
presence of one variable is associated with the absence of another variable
What is the name of the output of a t-test?
t statistic
What is a pooled t-test?
a regular t-test, assuming the variances for the 2 groups are the same
What are matched paired t-test?
Also what is this great for studying?
involves matching each person in one group with a person in a second group; applies to before and after measures and linked data
Draw a graph that helps determine which analytical tool to use.
