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

Here is the output (notice that when you check “Normality plots with tests), you get both Kolmogorov- Smirnov’s test and Shapiro - Wilk’s test). The significance (p) value is compared to the alpha level of .05. Reject the null hypothesis of a normal distribution (p ≤ α ) or retain (p > α ) the null hypothesis.

The p of .077 > .05, therefore retain the null hypothesis that the sample data is drawn from a normally distributed population.

Table 130: Test of normality

#4 – Advanced Approaches to Test for Normality

The Shapiro-Wilk test is conservative, so it is important to validate your findings by the visuals (the Q-Q plot and the histogram) to determine normality. Some statisticians suggest an additional step. Tabachnick & Fidell (2007) suggest examination of skewness and kurtosis. Essentially, they suggest dividing skewness (kurtosis) by its standard error. If it is greater than z +3.29 (p < .001, two-tailed test), it is a significant departure from normality. Cain, M.K., Zhang, Z. & Yuan, KH. Univariate and multivariate skewness and kurtosis for measuring nonnormality: Prevalence, influence and estimation. Behaviol Research 49, 1716 – 1735 (2017). https://doi.org/10.3758/s13428-016-0814-1

Question 1: .What is the difference between coding and numerical coding?

a. coding is used for qualitative data and numerical coding is used for quantitative data b. numerical coding is more scientific than coding c. numerical coding includes an extra step of assigning numbers to categories d. coding does not require you to categorize the data Answer: c Question 2 : Which of the following measures of central tendency is the most sensitive to change? a. mode b. median c. mean d. z score Answer: c

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