Terms  Definitions 

homogeneous 
similar in makeup

standardized value 
z  score

symmetric 
type of distribution shape; approximately mirrorimage; no data set is perfect mirrorimage

Confidence Level 
the estimated probability parameter lies within a given range of numbers

contingency table 
displays counts and, sometimes, percentages of individuals falling into named categories on two or more variables; categorizes the individuals on all variables at once, to reveal possible patterns in one variable that may be contingent on the category of the other

trial 
the sequence of several components representing events that we are pretending will take place

outcomes 
the results of a chance phenomenon

3 Experiment 
and experiment that manipulates factor levels to create

Replication 
The repetition of an experiment in order to test the validity of its conclusion.

histogram 
uses adjacent bars to show the distribution of vales in a quantitative variable; each bar represents the frequency (or relative frequency) of values falling in an interval of values

direction 
a positive ____ or association means that, in general, as one variable increases, so does the other; when increases in one variable generally correspond to decreases in the other, the association is negative

multistage sampling 
sampling schemes that combine several different sampling methods at different stages

strata 
when groups of experimental units are similar, they are gathered into these groups

µ 
The average of the population of data

Chebyshev's inequality 
the percent of observations falling within k standard deviations of the mean is at least (100)(1 (1/k^2))

Normal distributions 
Normal distributions are described by a special family of bellshapes symmetric density curves, called normal curves. The mean μ and standard deviation σ completely specify a normal distribution N (μ, σ). The mean is the center of the curve and σ is the distance from μ to the inflection points on either side.

3 Retrospective study 
An observational study where subjects are selected and their previous conditions are determined

Statistically significant 
a term used to describe research results when the outcome of a statistical test indicates that the probability of those results occurring by chance is small

variance 
the sum of squared deviations from the mean, divided by the count minus one

confounding 
when the results of an experiment can be determined because a variable has not be accounted for and has interferred with your results

sampling variability 
the natural tendency of randomly drawn samples to differ, one from another

right skewed 
type of distribution shape; right tail is longer than left

Density curve 
Describes the overall pattern of a distribution. Total area = 1. Area beneath curve gives proportions of observations.

Probability Sample 
A probability sample gives each member of the population a known chance (greater than zero) to be selected.

3 Confounding 
Wen the levels of one factor are associated with the levels of another factor in such a way that their effects cannot be separated

percentile 
the ith ___ is the number that falls above i% of the data

Interquartile Range (IQR) 
the third quartile minus the first quartile

matched pairs 
type of study in which subjects who are similar in ways not under study may be grouped together and then compared with each other on the variables of interest

positively associated 
when above average values of one tend to accompany above the average value of others and below also tend to come together

3 Convenience sample 
When a sample is created by subjects that are convenient

Sampling without Replacement 
Selecting an item and not returning it to group before resampling.

third quartile 
the value where 75% of the data falls below it in an ordered list

^p; sample proportion 
The number of successes divided by the number of trials (n)

Facts about probability 
1. Any probability is a number between 0 and 1.
2. All possible outcomes together must have probability 1. 3. The probability that an event does not occur is 1 minus the probability that the event does occur. 4. If two events have no outcome in common, the probability that one or the other occurs is the sum of their individual probabilities. 
A and B, A /\ B 
the event consisting of outcomes common to both events

Outlier 
1.5 x IQR below Q1 or 1.5 x IQR above Q3.

Mathematical model (model) 
The LSRL is a model for the data. If the data seems to show a linear trend, then it would be appropriate to try and fit an LSRL to the data.

Leave a Comment ({[ getComments().length ]})
Comments ({[ getComments().length ]})
{[ comment.comment ]}