2022 Introduction to Statistics in Research Mitchell 2nd ed

I N T R O T O R E S E A R C H : D A T A V I S U A L I Z A T I O N & C O M M O N S T A T T E S T S

#2 – Test Normal Distribution graphically – Histogram Use the following steps in SPSS to produce a histogram: Analyze > Descriptive Statistics > Explore (put Complaints in dependent list) > Plots: check histogram > Continue OK

You should see a histogram, but we are not done yet. Double click the histogram and look for this

button in the chart-editor window to add a normal curve. There is a peak in the middle and it is fairly symmetrical, thus the

assumption of normality has been met.

Table 128: Histogram to test normal distribution

#3 – Test Normal Distribution numerically

Use the following steps in SPSS to test normality using the Shapiro- Wilk’s test: Analyze > Descriptive Statistics > Explore > (put Complaints in dependent list) > Plots: check Normality plots with tests > Continue OK (Note that you could collect both a histogram and normality plots with tests on the same exploration pop- up.)

For a small sample like the one used here, the Shapiro- Wilk’s W test can be used to determine if the distribution is normal. This is a small sample so the Shapiro- Wilk’s W test is better than the Kolmogorov-Smirnov test. SPSS can do either of these.

The null hypothesis for is that the sample data have been drawn from a normally distributed population.

Table 129: Test normal distribution numerically

Statistics made easy!!! Learn about t-test, the chi square test, the p value and more

This video by Greg Martin at Global Health. He ’ s from Ireland, so his accent is an added bonus! This introduction to stats will give you an understanding of how to apply statistical tests to different types of data. Location: https://youtu.be/I10q6fjPxJ0

Martin, G. (2021). Statistics made easy!!! Learn about t-test, the chi square test, the p value and more. Global Health with Greg Martin. [Video file]. YouTube. https://youtu.be/I10q6fjPxJ0

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