statistics final 2
Terms
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- statistics
- science of collecting, summarizing, analyzing, and interpreting data.
- descriptive statistics
- summarizing data
- inferential statistics
- analyzing and interpreting
- probablility
- determining relative frequency of events
- deductive thought process
- known facts imply new facts
- inductive thought process
- observations infer properties
- frequency distribitution
- 2 column table including values of the variable and its frequency
- stem and leaf plot
- displays distribution of values of quantitative variables.
- skewness
- direction of longest tail
- histogram
- graphs values of quantitative variables on x-axis and frequency on Y-axis
- Sample mean (formula)
- X/=Exi/n
- variance (symbol)
- s^2, distance from mean
- sample Standard deviation (symbol)
- s, square root of variance
- scatterplot
- plot elements as a point on 2-d axis
- linear correlation coefficient
- stregnth of relationship between x and y (r)
- probability experiment
- random process, distinct outcomes
- outcome
- result of probability experiment
- sample space
- S, set of all possible outcomes of probability experiment
- event
- collection of outcomes from S
- null event
- no outcomes
- simple event
- one outcome
- union event (U)
- or
- Intersection event ()
- and
- mutually exclusive
- no outcomes in common
- formula for equally likely outcomes
- P(A)=# of outcomes in A/# of outcomes in S
- Independent events
- knowing whether one event occurs doesn't change the probability that the other event occurs
- complement rule (formula)
- P(A)=1-P(A')
- addition rule (formula)
- P(AUB)=P(A)+P(B)
- multiplication rule (formula)
- P(AB)=P(A)P(B)
- condtional probability rule (formula)
- P(BlA)=P(AB)/P(A)
- random variable
- assign numbers to each outcome of a probability experiment.
- discrete random variable
- random variable that takes finite number of values
- probability distribution of a discrete random variable
- assigns probabilities to each value of a drv
- mean of a discrete random variable (formula)
- E(all y)yp(y)
- continuous random variable
- random variable whose value can be any number in 1 or more intervals
- probability density funtion of a continuous random variable
- f(y) likelihood
- standard normal random variable (symbol)
- Z, table-zx
- standardizing random variable (formula)
- z=Y-u/e
- population
- large set of elements of interest
- parameter
- characteristic of a population
- sample
- draw random with replacement from a population
- statistic
- characteristic of a sample
- point estimator
- random process used to obtain guess for a parameter
- estimate
- number obtained from point estimator
- unbiased estimator
- statistic used to estimate a parameter if the mean of its sampling distribution is equal to its parameter
- sampling distribution X/(formula)
- N(u,e/SRn)
- interval estimator
- point estimator +- MoE
- MoE
- table value x standard error
- hypothesis testing
- decision making process between two alternative statements about a population
- type 1 error
- rejecting true null hypothesis
- type 2 error
- failing to reject false null hypothesis
- level of significance
- compares severity of errors
- test statistic
- describes Ho
- rejection region
- values of the test statistic that reject Ho and support Ha
- S.v. of T.s.
- computed value of the test statistic using data collected
- p-value
- probablity of test statistic being more supportive of Ha
- critical value
- cut off between rejection region and acceptance region
- independent random samples
- random samples taken from each popuation with none of the elements in either sample related to any element in other samples
- pooled estimator
- weighted average of 2 sample variances
- response variable
- random variable whose value is determined by a random process
- explanatory variable
- variable controlled by experimenter
- goals of regression analysis
- determine relationship between the explanatory variable and response variable and find the best fit line
- outlier (formula)
- Q1-1.5 x IQR, Q3+1.5 x IQR
- sample proportion (formula)
- p^, x1+x2+x3.../n