Stat exam 1 review

x bar means what?
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sigma xbar= ___(sigma x)/(sq root of n)z=___ when using one data point(x-mu)/(sigma)z=___ when using multiple data points((xbar-mu)/(sigma)) / (sq root of n)parametera numerical measurement describing some characteristic of a populationdiscretedata result when the number of possible values is finite or countable. i.e) number of eggs in a cartonstatistica numerical measurement of a samplecontinousnumerical data that results from infinitely many possibilities. i.e) how much milk a cow makes in a day--> 3.485947 gallonsnominal level of measurementdata consists of names, labels, and categories only. Data can not be arranged (yellow, blue, orange)ordinal level of measurementCan be arranged but data value isn't given (A,B,C,D,F)interval level of measurementCan be arranged, is like ordinal except the difference between two data values is meaningful (like the years 1000, 1938, 2019)Ratio level of measurementmodified level of measurement to include natural zero as a starting point. Like the price of textbooks or age of a building.Frequency distributionlists data values along with frequencies or counts (this is a frequency table)Histogrambar chartdot plotgraph where all data points are plottedscatterplotdata points plotted with X and Y values for each pointtime seriesgraph with data collected from different points in timeCapital Sigma means what?denotes the addition of a set of valuess=___sigma =___variancethe variance of a set of values is a measure of variation equal to the square of the standard deviationIQR=___Q3-Q1what makes a normal distribution standard?mu=0 and sigma=1Density curvethe graph of a continuous probability distribution. It must have the total area under the curve=1empirical rule68% within 1 stdev, 95% within 2 stdev, 99.7% within 3 stdevHow would you find the score that determines the bottom 55% of IQ test results?Use x=mu+(z*sigma)The standard deviation of the distribution of sample means is(sigma*x)/(sq root of n)what is the standard deviation of the distribution of sample means often called and what is the equation?The standard error of the mean. (sigma*x)/(sq root of n)For Z what is alpha equal to? a/21- confidence level. Ex.) 95% confidence=a=.05confidence interval for population meanmargin of error ( written as E)= what when dealing with z scores?Z * sigma/sq root of n a/2formula to determine sample sizen= ((Z alpha/2)*sigma)) / E --> ALL SQUAREDmargin of error ( written as E)= what when dealing with t (so no sigma known) scores?E= T alpha/2 * (s)/(sq root of n)T=___(xbar-mu)/(s/sq root of n)degrees of freedom=__n-1confidence interval for muA-muB(xbar2-xbar1)- E < mu2-mu1< (xbar2-xbar1)+EWhat does E equal when finding muA-muB and sigma is known?E= Z alpha/2 * the square root of:( sigma1^2/n1) + (sigma2^2/n2)pooled standard deviationstandard error for the differenceSE(xbar2-xbar1)= SP * square root of: (1/n1)+(1/n2)If we don't know sigma and we want the confidence interval for muA-muB what do we use for E?E= T alpha/2, df * (SP * square root of: (1/n1+ 1/n2)