# statistics

Statistics is a branch of mathematics that allows you to draw conclusions about a large group of people based on information collected from a smaller group. It's also a tough college math course.

Say an Australian study reports that 45% of fifteen-year-old Australians like grape soda. The people who conducted that study didn't interview 45% of Australian fifteen-year-olds; they interviewed perhaps a fraction of the Australian fifteen-year-old population and based their conclusions about the entire population on that. This is the essence of statistics, and the uncertainty surrounding such studies is one reason why people who practice statistics have to take tough college courses.

Definitions of statistics
1

### n a branch of applied mathematics concerned with the collection and interpretation of quantitative data and the use of probability theory to estimate population parameters

Types:
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correlation, correlational statistics
a statistical relation between two or more variables such that systematic changes in the value of one variable are accompanied by systematic changes in the other
nonparametric statistics
the branch of statistics dealing with variables without making assumptions about the form or the parameters of their distribution
biometrics, biometry, biostatistics
a branch of biology that studies biological phenomena and observations by means of statistical analysis
curvilinear correlation, nonlinear correlation, skew correlation
any correlation in which the rates of change of the variables is not constant
partial correlation
a correlation between two variables when the effects of one or more related variables are removed
direct correlation, positive correlation
a correlation in which large values of one variable are associated with large values of the other and small with small; the correlation coefficient is between 0 and +1
indirect correlation, negative correlation
a correlation in which large values of one variable are associated with small values of the other; the correlation coefficient is between 0 and -1
spurious correlation
a correlation between two variables (e.g., between the number of electric motors in the home and grades at school) that does not result from any direct relation between them (buying electric motors will not raise grades) but from their relation to other variables
Type of:
applied math, applied mathematics
the branches of mathematics that are involved in the study of the physical or biological or sociological world