What is the first step in the process of calculating standard deviation?

The first step in calculating the standard deviation involves determining the variance, which requires summing the squared differences between each data point and the mean. This process includes calculating the "sum of squares," where each data point is subtracted from the mean, squared to remove negative values, and then summed together.

Focusing specifically on how this applies to the stated choices, the phrase "sum of squares ratios" points to an important part of the variance calculation process, as it lays the groundwork for finding the average of those squared differences. Once the sum of the squared differences is obtained, the next steps involve dividing that sum by the number of data points (or the number of data points minus one for a sample, depending on whether you're calculating the population or sample standard deviation) to find the variance. Finally, the standard deviation is found by taking the square root of the variance.

Thus, identifying the sum of squares as a foundational step signifies an understanding of how the characteristics of data points relative to their mean are utilized in measuring the overall dispersion within a data set.