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  • 00:05

    HERSCHEL KNAPP: Welcome to Introductory Statistics UsingSPSS, Second Edition.This video shows how to process the Pearsoncorrelation and regression.You can watch the entire video or use the time sliderto navigate directly to any time point.[Correlation and Regression - Pearson, Overview]

  • 00:25

    HERSCHEL KNAPP [continued]: Correlation and regression analysiscomputes the nature of the relationship between twocontinuous variables.The relationship can be characterizedusing two parameters, direction and strength.The regression ranges between -1 and +1.The regression sign indicates the direction

  • 00:47

    HERSCHEL KNAPP [continued]: of the correlation.Positive correlations occur when the variablesmove in the same direction.When x goes up, y goes up.Or when x goes down, y goes down.Negative correlations occur when the variablesmove in opposite directions.

  • 01:07

    HERSCHEL KNAPP [continued]: When x goes up, y goes down.Or when x goes down, y goes up.The regression value indicates the strengthof the correlation.Values nearer to -1 or +1 are stronger than values nearerto zero.

  • 01:28

    HERSCHEL KNAPP [continued]: To better conceptualize the data,a scatterplot with a regression line is useful.Each point represents two values gathered from each individual.For example, this point represents two valuesgathered from one of the students, whospent 107 minutes taking the exam and earned a grade of 83.

  • 01:50

    HERSCHEL KNAPP [continued]: The regression line can be thoughtof as the average pathway through the points.To better comprehend the notion of regression,consider these three examples.Here we see a strong positive correlationbetween the time spent taking the exam and the gradeon the exam, where a lower test-taking time is paired

  • 02:11

    HERSCHEL KNAPP [continued]: with lower grades and higher test-taking timeis paired with higher grades.In the second scatterplot we see a strong negative correlationbetween test-taking time and grade,where lower test-taking time is paired with higher grades,and higher test-taking time is paired with lower grades.

  • 02:33

    HERSCHEL KNAPP [continued]: In the third example, we see a fairly weak correlationbetween test-taking time and grade,where test-taking time has virtually no correlationwith the grades.[Correlation and Regression - Pearson, Pretest Checklist]Before running the Pearson correlation and regressionanalysis, there are three pretest criteria

  • 02:54

    HERSCHEL KNAPP [continued]: that need to be met.First, the data for each of the two groupsshould be normally distributed.We can check for this by observing a histogramwith a normal curve for each variable.The second and third criteria, linearity and homoscedasticity,can be verified by observing the scatterplot with the regression

  • 03:15

    HERSCHEL KNAPP [continued]: line.This example uses the dataset Ch 08 - Example 01 -Correlation and Regression - Pearson.sav.This dataset contains three variables.Name is a string variable, along with twocontinuous numeric variables.

  • 03:37

    HERSCHEL KNAPP [continued]: Time is the number of minutes that each studentspent on the exam, and Grade is the score on the exam.To check for normality, order histograms with normal curvesfor the two variables that will beinvolved in the correlation, Time and Grade.Click on Analyze, Descriptive Statistics, Frequencies.

  • 04:00

    HERSCHEL KNAPP [continued]: Move Time and Grade into Variables and click Charts.Select Histogram With Normal Curve, click Continueand uncheck Display Frequency Table.Click OK and it'll process.

  • 04:21

    HERSCHEL KNAPP [continued]: The symmetrical curve on the histogram for Timeshows a normal distribution.And the curve on the histogram for Gradealso shows a normal distribution.The pretest criteria of normality is satisfied.To finalize the pretest checklist,we'll order a scatterplot with regression line.

  • 04:42

    HERSCHEL KNAPP [continued]: This will also give us a more comprehensive understandingof the relationship between Time and Grade.Click on Graphs, Chart Builder.In the Choose From list, select Scatter/Dotand select the Simple Scatter option.

  • 05:04

    HERSCHEL KNAPP [continued]: Drag Time to the x-axis and Grade to the y-axis.Click OK, and it'll process.To order the regression line, double-click on the scatterplotand click on the Add Fit Line at Total icon.In terms of linearity, we see that the points

  • 05:25

    HERSCHEL KNAPP [continued]: lie in a fairly straight line.There are no unexpected curves or twistsin the arrangement of the points.This satisfies the linearity criteria.As for homoscedasticity, we see that the field of pointsis thicker in the middle and tapers at the ends.This satisfies the homoscedasticity criteria.

  • 05:47

    HERSCHEL KNAPP [continued]: [Correlation and Regression - Pearson Test Run]To process a Pearson correlational analysis,click on Analyze, Correlate, Bivariate.Move Time and Grade to Variables.Click OK, and it'll process.

  • 06:09

    HERSCHEL KNAPP [continued]: [Correlation and Regression - Pearson, Results]The Correlations table shows a strong positive correlationof 0.815 between Time and Grade.We also see that the P value is less than 0.05,suggesting that this is a statisticallysignificant correlation.

  • 06:35

    HERSCHEL KNAPP [continued]: This concludes this video.

Video Info

Series Name: Introductory Statistics Using SPSS

Episode: 10

Publisher: SAGE Publications, Inc.

Publication Year: 2017

Video Type:Tutorial

Methods: Pearson's correlation coefficient, Regression analysis, SPSS

Keywords: mathematical computing; mathematical concepts; Software

Segment Info

Segment Num.: 1

Persons Discussed:

Events Discussed:

Keywords:

Abstract

In chapter 10 of his series on using SPSS, Professor Herschel Knapp explains statistical regression and the criteria for running Pearson's Correlation Coefficient. His demonstration offers numerous histograms and step-by-step guidance in SPSS to support the discussion.

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Correlation and Regression – Pearson

In chapter 10 of his series on using SPSS, Professor Herschel Knapp explains statistical regression and the criteria for running Pearson's Correlation Coefficient. His demonstration offers numerous histograms and step-by-step guidance in SPSS to support the discussion.

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