Biomed Stats
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nonnumeric or narrative info
qualitative data

numeric or quantifiable info (ex: weights of kindergartners)
quantitative

variable the researcher manipulates
independent variable

the variable the researcher is attempting to prove.
dependent variable

infinite number of values between two points
cannot be 1.5 children, etc...
discrete variable

has, in theory, an infinite number of values between two points
ex: body temp
continuous variable

NOIR
 nominal
 ordinal
 interval
 ratio

lowest level
assigns characteristics into categories
nominal or named variable

next in hierarchy of measurement
rank order of variable along some dimension
ordinal or Order

attribute is rankordered on a scale that has equal distances between points on that scale
interval = equal distances

equal distances between score units and which has a true, meaningful zero point
(a true ratio can be calculated)
ratio measurement

higher levels of measurement provide ...
 more information
 can be analyzed with more powerful stat tools

a subset of a population
ideally selected to be representative of the population
sample

the entire set of individuals having common characteristics
population

used to describe and summarize data set
allows us to describe, compare, determine a relationship
usually straightforward
descriptive

draw conclusion about a single variable in a population
evaluate relationships between variables
are the relationships "real"?
inferential

Type of stat that measures:
existence of relationship between x and y
magnitude of the strength of relationship
the nature of the relationship
inferential stats

one variable being described
univariate

two variables being compared
bivariate

more that two variables being compared
multivariate

Name the two kinds of frequency

symbol: f
number of times a score occurs
absolute frequency

most commonly percent %=(f/N) X 100
proportion of times a score occurs
relative frequency

Name the 5 basic shapes of charts
 modality
 symmetry and skewness
 kurtosis
 central tendency
 variability

modality
 peaks or high points in the data
 unimodal
 bimodal
 multimodal

draw a line through the center and produces mirro images
symmetrical

distribution is lopsided or skewed
asymmetrical

the skewed tail points to the right
positive skewness

the skewed tail points to the left
negative skewness

refers to how pointy the peak of distribution
how concentrated the middle of the distribution
 kurtosis
 platykurtic (low, flattened)
 leptokurtotic (high narrow)

Ideal distribution
bellshaped curve
unimodal
symmetrical
normal distribution

when do you use a bar graph?
discrete info

when do you use a histogram
continuous info

the point at 25% below and 75% above the median
Quartile 1 (Q1)

the point at 50% below and 50% above the median
Quartile 2 (Q2)

the point at 75% below and 25% above the median
Quartile 3 (Q3)