Lecture_3_DescriptiveStats.pptx - DESCRIPTIVE STATISTICS...

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DESCRIPTIVE STATISTICSIntermediate Stats LabSTA 3163L-006Lecture 3
TODAY’S GOALSTo learn where the middle of your data set is (central tendency)oMean, Median, ModeTo learn how broad the variables in your data set are (statistical dispersion)oRange, Variance, Standard DeviationTo learn the shape of your distributionoNormal Distributions
TWO TYPES OF STATISTICSDESCRIPTIVE STATISTICSDescribe a sampleMeanStandard DeviationVarianceINFERENTIAL STATISTICSAllow researchers to infer characteristics of a population3
DESCRIPTIVE STATISTICSEasily telling people about your dataCollecting data can be easy and fun. But sometimes it can be hard to tell other people about what you have found. That’s why we use statistics. Two kinds of statistics are frequently used to describe data. They are measures of central tendency and dispersion. These are often calleddescriptive statisticsbecause they can help youdescribeyour data.Statistics Help For Students (2008). What are measures of central tendency and dispersion?Retrieved from
MEASURES OF CENTRAL TENDENCY
THREE MEASURES OF CENTRAL TENDENCY:Mean – average data point of all the variables in your data setMedian – data point found in middleMode – data point found which occurs most often5
MEAN, MEDIAN AND MODEThese are all measures of central tendency. They help summarize a bunch of scores with a single number. Suppose you want to describe a bunch of data that you collected to a friend for a particular variable like height of students in your class. One way would be to read each height you recorded to your friend. Your friend would listen to all of the heights and then come to a conclusion about how tall students generally are in your class. But this would take too much time. Especially if you are in a class of 200 or 300 students! Another way to communicate with your friend would be to use measures of central tendency like the mean, median, and mode. They help you summarize bunches of numbers with one or just a few numbers. They make telling people about your data easy.Statistics Help For Students (2008). What are measures of central tendency and dispersion?Retrieved from
MODEIn a frequency distribution, the modeis the score or category that has the greatest frequency. The data point which occurs most frequently.oModes can be calculated for all types of data (nominal, interval, ordinal and ratio).

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