Statistical Transformations and Normality

Dr. Gandhi's video tutorial explains how to conduct a square root transformation on skewed variables using SPSS. The tutorial covers the transformation process for both positively and negatively skewed variables, testing the normality of transformed data, and converting results back to original units. The video emphasizes the importance of data transformation in meeting the assumptions of parametric statistics, particularly in counseling research.

What is a common assumption of parametric statistics in counseling research?

• The dependent variable is positively skewed.

• The dependent variable is normally distributed.

• The independent variable is negatively skewed.

• The independent variable is normally distributed.

Why might researchers apply a square root transformation to their data?

• To make the data more positively skewed.

• To increase the sample size.

• To decrease the sample size.

• To achieve a normal distribution.

What is the first step in conducting a square root transformation on a positively skewed variable in SPSS?

• Select 'Analyze' and then 'Descriptive Statistics'.

• Select 'Graphs' and then 'Chart Builder'.

• Select 'Data' and then 'Sort Cases'.

• Select 'Transform' and then 'Compute Variable'.

What function is used in SPSS to perform a square root transformation?

• LOG

• EXP

• ABS

• SQRT

What is the purpose of reflection when transforming a negatively skewed variable?

• To make the variable positively skewed.

• To decrease the skewness.

• To increase the skewness.

• To make the variable normally distributed.

How is the reflection of a negatively skewed variable calculated?

• Maximum value minus 1 plus the variable.

• Maximum value plus 1 minus the variable.

• Minimum value plus 1 minus the variable.

• Minimum value minus 1 plus the variable.

What statistical test is used to assess the normality of transformed variables?

• Chi-square test

• Shapiro-Wilk test

• ANOVA

• T-test

What does a p-value greater than 0.05 in the Shapiro-Wilk test indicate?

• The variable is negatively skewed.

• The variable is positively skewed.

• The variable is not normally distributed.

• The variable is normally distributed.

What does a histogram with a tail pointing to the right indicate?

• A normal distribution

• A negative skew

• A positive skew

• A uniform distribution

What is the significance of outliers in a box plot?

• They indicate a uniform distribution.

• They indicate a normal distribution.

• They indicate no skewness in the data.

• They indicate skewness in the data.