Normal Distribution

The normal distribution is a hypothetical symmetrical distribution used to make comparisons among scores or to make other kinds of statistical decisions. The shape of this distribution is often referred to as “bell shaped” or colloquially called the “bell curve.” This shape implies that the majority of scores lie close to the center of the distribution, and as scores drift from the center, their frequency decreases.

Normal distributions belong to the family of continuous probability distributions or probability density functions. A probability density function is a function meant to communicate the likelihood of a random variable to assume a given value. This function is graphed by plotting the variable, x, by the probability of that variable occurring, y. These normal probability distributions are characterized by the ...