Exam 3 Tuesday 4 15 in class The exam will consist of 25 multiple choice questions 2 pts each 50 pts 15 points short answer 10 points short essays Total 75 points Pay close attention to recommendations regarding research methodology or the pros and cons of various approaches discussed in class This is what you need to know for the exam 3 27 14 Descriptive Data Analysis Know the difference between a statistic and a parameter Statistic Numerical description of a sample of your population of interest Parameter true value of your statistic in the actual population Know the difference between descriptive and inferential statistics Descriptive simply represent your sample on demographic characteristics or variables on interest Inferential allow one to estimate how confident we are that what is true of our sample data is true of the actual population Know measures of central tendency and what types of data they can be used with mode median mean Skewness responses clustered towards one end Central tendency the most common average response The spread of responses Mode the most often value o Only measure that can be used with nominal level variables o Not appropriate for nominal variables only ordinal and up Median middle point Mean average ratio o Not appropriate for nominal variables only truly appropriate for interval and Know which types of data bar charts and histograms are appropriate for depicting Unimodal one mode Bimodal when possible for a variable to have two modes i e exam question Histogram used to show distribution of ordinal and up Understand that extreme scores affect the mean more than the median Understand skewness and outliers When responses are clustered towards one end of the distribution Outliers are an extremely high or low value that doesn t fit with the rest of the data Outliers effect range Know standard deviation and normal distribution Standard deviation square root of the variance Normal distribution bell curve Cowan Cowan 2002 know their central point about the importance of intervention studies for providing evidence for causal effects Intervention studies provide evidence for causal effects Intervention studies have helped the field draw some conclusions about the causal forces operating form family processes to child and adolescent outcomes