The normal curve is also known as a bell-shaped curve and represents a normal distribution. The distribution is based on a probability distribution for a continuous random variable. The area under the curve is equal to 1 and represents the sum of all probabilities for a random variable. The mean of the normal curve is 0 with a standard deviation of 1. The mean, median, and mode are all the same on a normal curve with a unimodal distribution and appear in the body of the normal curve. A unimodal distribution is a normal curve with only one peak. A normal curve is also symmetrical. When folded in half the left side will mirror the right side. As a general rule 68% of the data falls within one standard deviation of the mean, 95% falls within two standard deviations of the mean, and 99.7% falls within three standard deviations of the mean. Common examples using the normal distribution include IQ scores and test scores. The normal curve can be used to determine percentile ranks and z-scores. The parts of the normal curve, different deviations of the normal curve, properties of the normal curve, and uses of the normal curve will be discussed in depth.