# Test 1 Elementary Stat UTA

Classified in Mathematics

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*MAKE SURE TO READ THE QUESTIONS CAREFULLY!!!*

*Chapter 3*** Missing variable**: x=given Median*2-((1 of 2) median numbers if even): ascending order:::

**- (U*N of unreadable)-(U*N of readable):::degrees of freedom=1 # of freedom is lost:::**

*unreadable score***CHEBS-**K=Deviaton::Calculate time % within K Dev of mean- (1-1/k^2)100=%:::

**Find Values**- find x K devs from mean- (mean-K*given standard dev)=XLow...(mean+k*given standard dev)= XHigh::

**Find % within times Xlow-Xhigh:**K=(XHigh - Mean)/Given Standard dev....Then do chebs- (1-1/k^2)100=%:::

**Z SCORE Simplified:**(Mean-Given Mean)/Given Standard Dev=ZScore:::

**Find min score accepted:**(Min devs)*(Given Devs)+(Mean)=Min Score:::

**Weighted Mean:**Chart Xi / Wi /XiWi..

**Use Empirical Rule if dist. Is bell shaped. Sum of Dev's = 0: range does not use all observations::The more Dispersion the Higher the Standard of Dev**

*Chapt 2***Stat=**Science of organizing data to draw conclusions::

**Descriptive Stat**=describe date through numerical summaries or graphs, "for those surveyed"::

**Variables=**characteristics if indiv in pop::

**Discrete**=you can count 1,2,3::

**Cont=**you measure 1.2,1.34,1.675 etc::

**Nominal**-Name,

**Ordinal**- Nom+rank/order,

**Interval**- 0 has no meaning equal space between #'s,

**Ratio**- 0 has meaning can be any #'s (factory quest)::

**Response**-what is being studied,

**Explanatory-**variable that affects response,

**Factor-**variable whose effect on the response variable is to be assessed by the experimenter

**Confounding-**not separating variables,

**Lurking-**explanatory variable not considered::Studies only show assoc.::

**Cross-Sectional-**Group of people in short amount of time,

**Case-Control-**Looking to past for answers,

**Cohort-**Group of people over a long time.

**Frame-**List of indiv being studied, not always accurate because pop is always changing,

**Simple**

**Random Sampling-**Pick names out of a hat or chart, not always preferred expensive,

**Stratified-Separating**pop into different groups then obtaining a simple random of indiv from each group,

**Systematic Random-**selecting every nth indiv, Does not require frame; K= Pop/Sample, p, p+k, ...P+(N-1)*k :::

**Cluster-**Randomly selecting group then obtaining sample from all,

**Bias-**sample does not represent pop, Non

**Sampling Bias-**under coverage(smaller in sample) or favors one part of pop, may result from non response or improperly worded questions,

**Experiment-**study conducted to determine the effect of 1 or more explanatory has on a response,

**Treatment-**combination of the values of factor,

**Experimental Unit-**person being studied,

**Matched Pairs-**before and after, husband and wife::

**Relative Freqs**-add up to 1::

**Charts-**Stem and leaf plots not good for large data but show original data, Histograms- Organize data of all sizes. Difference between values between quarters- (High - Low) / High, difference values of highest and lowest (high-low) / Low::

**Class Width-**(Max entry - Low entry)/Number of entries:: Quantitive variables are required for time plots:: > = greater than, <= Less than