For Test Bring Pencil Calculator and Reference Sheet both sides no examples BMGT230 EXAM 1 REVIEW Variables the characteristics recorded about each individual or case Qualitative Categorical Quantitative Numberical Ordinal Ordered Nominal No Order Dicrete gap betwen numbers ex kids in household Continuous Arbitrarily close together Ratio Data has a meaningful zero age income etc Interval Data no meaningful zero temperature Time Series measure the same variable at regular intervals over time Cross sectional data where several variables are measured at the same point Sampling and Surveys Bias when the sample is not representative of the population In order to get rid of bias you must randomize Selection Bias leaving out a certain group of individuals of the population Nonresponse Bias when someone doesn t respond to the survey Response Bias person lies to the interviewer the interviewer gives a leading question Sampling Frame effective population population you have access to ideally it is the entire population Sampling error the variation from sample to sample Sampling Techniques Simple Random Sample SRS each individual has the same chance of being selected Stratified Groups strata are different from one another but similar within each strata Take SRS within all strata Combine all SRS samples Ex Take each separate class in the business school and do a SRS of each class Take the selected students from the classes and combine them to make your sample Cluster Groups clusters are similar to each other Take SRS of all the clusters Look at all the individuals within the selected clusters Systematic sampling method where you systematically select each person such as picking every tenth person on a list of people The first person is selected at random and then you go down the list and select every 10th Convenience choosing your sample due to the convenience of it Voluntary a survey that is not required Ex An online poll Marginal Distribution distribution of one variable in respect to the other one based on column totals or row totals Conditional Distribution shows the distribution of one variable for just those cases that satisfy a condition on another Categorical Data Two way tables Bar Graphs Pie Charts Simpson Paradox Numerical Data Histograms Stem and Leaf Plots How to describe numerical data Shape number of modes skewness Center mean if there are no outliers median if there are outliers Spread range if there are no outliers IQR Standard Deviation 5 summary Minimum Q1 Median Q3 Maximum Correlation Coefficient r if r 0 there is no linear association if r is 1 or 1 the points are on a line 1 r is between 1 and 1 2 3 4 r is invariant to scale changes 5 r is not robust Interpreting the Slope As x increases by 1 unit the response on average changes by the value of the slope Residuals observed predicted Sum of the residuals 0 Conditions Quantitative Data Condition Linearity scatter plot or residual plot Independence if it s a random sample Equal Spread Outliers no outliers Probability Rules 1 OR rule P A P B P A and B 2 Compliment rule P compliment of A 1 P A 3 And Rule P A and B P A x P B if A and B are independent 4 General And Rule P A and B P A x P B given A and visa versa I did not put the formulas on here because we will put them on our reference sheets and they are too hard to put them on the computer If you need them just ask me and I will write them out for you
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