Normal Distribution Essay Example | Topics and Well Written Essays - 500 words

Normal Distribution - Essay Example For a group of statistics to be reliable, they need to have a normal or bell-shaped curve. In order to help achieve this outcome, the mean will need to be as close to the center as possible. Also, the standard deviation will likely be small in order to help the curve remain tall and narrow. The reason why normal distribution is so useful computationally is that it allows us to make conclusions from the data at hand. Let’s say, for instance, that a graph was skewed either to the left of the right. It would be very hard to come to any conclusive theories based off the data. This is because the data would not be reliable and could not be used to make any assumptions. Normal distribution is symmetrical, so it is easy to make conclusions just by looking at it with the naked eye. Other forms of data may require detailed calculations in order to make an inference or hypothesis. If a curve displays normal distribution, then the mean will be exactly the same figure as the median and the mode. Also, the standard deviations will be within a set range of numbers. If a curve is bell-shaped, then more than two thirds of the distribution (68%) will lie between one standard deviation of the mean. More than this, 95% of the data will be located within two standard deviations of the mean. All these figures are useful when working out probability. It is possible to say that there is a certain percent of a variable falling within a certain range on the graph. The tests such as Goodness of Fit, Independence, and ANOVA all use other distributions because the data is not symmetrically aligned. It could be that the distribution is skewed, either to the left or the right, and thus it is not possible to come to a conclusion simply by looking at the graph. The occurrence of outliers is also likely in such a case. One such method is the Chi-square