What is the primary use of a normal probability plot?

The primary use of a normal probability plot is to assess if data follows a normal distribution. This statistical tool provides a visual technique to help determine if a dataset approximates a normal distribution by plotting observed data points against the expected values of a normal distribution. If the data points lie close to a straight line on the plot, it suggests that the data is normally distributed. This visual assessment is crucial in statistics, particularly when applying parametric tests that assume normality. The ability to quickly identify deviations from normality can inform subsequent data analysis techniques, making it an essential tool for statisticians and data analysts alike.

Displaying data visually serves a different purpose and does not specifically test for normality. Similarly, correlation coefficients are used to measure the strength and direction of relationships between variables, unrelated to whether the data is normally distributed. Predicting future data points involves regression analysis or time series forecasting, which are distinct from normality assessments. Thus, the primary focus of the normal probability plot is clearly its role in evaluating the normality of a dataset.