Standard deviation refers to the
a. statistics used to organize, summarize, and describe sample data
b. value within a given set of data in its original form
c. average distance between variable scores and the mean in a set of data
d. difference between the largest and smallest variable scores in a set of data

Standard deviation refers to the average distance between variable scores and the mean in a set of data. The answer is letter C. It is represented by the equation s = square root [Squared of the summation of (X - Xbar)/n - 1] where s is the standard deviation, x is the data, xbar is the mean of the given data and n is the number of population. It is also used to measure the dispersion of the data from the given set of points. 

Ican't do any of the other stuff, but i can get you started. the answer, i believe, is $2.50.