Black Men and Prison Recidivism

Today, we continued our discussion of Statistics and we were introduced to "measures of dispersion." Measures of dispersion indicate the extent to which values are spread around a central value. We took a closer look at mean. The measures of dispersion for mean are mean deviation, variance and standard deviation. Mean deviation is simply the mean of the absolute values of the differences between the data values and the mean (kind of like you're finding the mean of the mean.) Variance is the square of the mean deviation, and standard deviation is the square root of the variance.

In an effort to keep math "real-world" applicable, I decided to use measures of dispersion on something I'm interested in, and that is the rate of recidivism of Black males in New York State. Recidivism is the rate at which incarcerated individuals return to prison.

Above is a chart regarding the amount of prisoners in adult private prisons between the years 1987-2001. Clearly the overall trend of prisoners has since grown since the late '80s. Are these rates justified? And where are African-Americans in these numbers? This is the question I set out to answer using mean deviation, variance and standard deviation.