Vocab Quiz Flashcards
Absolute Value
Term used in mathematics to indicate distance of a point or number from the origin (zero point) of a number line or coordinate system. The symbol is a pair of vertical lines flanking the quantity whose absolute value is to be determined.
Alpha
Known as the significance level, alpha is the probability of a Type 1 Error (rejecting the null hypothesis when it is true)
Alternative Hypothesis
States what the researcher expects to find; it is the tentative answer to the research question that guides the entire study. Also called the research/causal hypothesis.
Array
In stats, arrays describe a data set arranged by numbers in rows and columns from least to greatest.
Association
Two variables’ correlation or association depending on when the values of one or the other tend to increase as the other increases. A positive association means a relationship exists between two variables and goes positive 100% of the time.
Beta
Probability of a Type II error (failing to reject the null when it should be). Basically means incorrectly concluding there is no statistical significance.
Bias
Prejudice in favor of or against one thing, person, or group compared with another, usually in a way considered to be unfair. Can be knowingly or unknowingly done.
Bimodal
Having or involving two modes, in particular of a statistical distribution having two maxima.
Categorical
Variable that can take on one of a limited and usually fixed number of possible values, assigning each individual or other unit of observation to a particular group or nominal category on the basis of some qualitative property.
Causality
Correlation between variables, however, does not automatically mean the change in one variable is the cause of change in the values of the other variable.
Causation
Indicates that one event is the result of the occurrence of the other event.
Central Tendency
A summary measure that attempts to describe a whole set of data with a single value that represents the middle or center of its distribution. There are three main measures of central tendency: the mean, median, and mode.
Cohort
A “group” or “panel”. Associated with types of studies used for determining the natural history of a condition.
Column
A vertical division
Confidence Interval
Estimated range of values likely to include an unknown population parameter; the estimated range being calculated from a given set of sample data
Contingency Table
A table showing the distribution of one variable in rows and another in columns, used to study the association between the two variables.
Continuous
There is an order to the variables: measured with mean and standard deviation OR made up of interval variable (distance between attributes have meaning) or ratio variable (possible to locate absolute zero).
Control group
Group of subjects closely resembling the treatment group in many demographic variables but not receiving the active medication or factor under study and thereby serving as a comparison group when treatment results are evaluated.
Correlated
Establish a mutual relationship or connection b/w variables
Counts
To determine the total numbers
Cross-sectional
A “one-time look”. All observations on a given subject are made at essentially one point in time. It is weaker than longitudinal (look over a period of time). It is used to describe some features of a population, such as prevalence (rather than incidence, which is longitudinal).
Cumulative
Of or relating to the total observed frequency of data, or the probability of a random variable, that is less than or equal to a specified value.
Dependent data
T-Test: performed to determine if there is a difference between before and after measurement of the same subjects (i.e. Dependent data)
Dependent variable
Variable being tested and measured in a scientific experiment (also called an outcome variable)
Descriptive
These studies provide information about a problem, condition, phenomenon….used to characterize it regarding a certain population.
Dichotomous
Nominal variable that only has two attributes.
Dispersion
Extent to which a distribution is spread; common measures include variance, SD, IQR.
Effect size
Descriptive statistic that estimates the strength of the relationship or difference between the true value and the hypothesized value. Can either be standardized or unstandardized. The standardized effect size is calculated as the difference between two means divided by the pooled SD of either sample, assuming eq. variances of both means.
ES = mean difference / SD
Also called the magnitude of the phenomenon of interest in the population. The smallest effect of clinical or practical significance (generally determined by an expert in the field, dictates how much of a difference would be clinically significant).
Experimental research
Experimental designs provide complete control over the intervention or causal factor being studied through randomization. Performs active observations that allow test systems to be altered.
Exponent
Almost every time e is used in a formula; raises its power.
False positive
Test result which incorrectly indicates that a particular condition or attribute is present (Type 1/alpha error).
False negative
Test result which incorrectly indicates that a particular condition or attribute is absent (Type 2/beta error).
Frequencies
Rate at which something occurs or is repeated over a particular period of time or in a given sample.
Homogeneity
Assumption that a time series sample is drawn from a stable/homogenous process
Incidence
Rate of new cases of the disease. Reported as the new number reported over a set period of time.
Independent
Statement of two variables being statistically independent, if the occurrence of one does not affect the probability of occurrence of the other. Two random variables are independent if the realization of one does not affect the probability distribution of the other.
