A Normal distribution is described by a Normal density curve Any particular Normal distribution is completely specified by two numbers: its mean ???? and its standard deviation ???? The mean of a Normal distribution is the center of the symmetric Normal curve The standard deviation is the distance from the center to the change-
Normal distribution The normal distribution is the most widely known and used of all distributions Because the normal distribution approximates many natural phenomena so well, it has developed into a standard of reference for many probability problems I Characteristics of the Normal distribution • Symmetric, bell shaped
normal then the transformed distribution will not be normal either One important use of the standard normal distribution is for converting between scores from a normal distribution and percentile ranks Areas under portions of the standard normal distribution are shown to the right About 68 ( 34 + 34) of the
IF 1) We have an independent random sample of n observations X 1 X n 2) The X 1 X n are all from the same distribution, whatever that is 3) This distribution has mean =
Perhaps the most important ideal distribution used is the 'normal' distribution (Figure 6 1) Once one understands the characteristics of the normal distribution, knowledge of other distributions is easily obtained Figure 6 1 The normal distribution Most people are familiar with the normal distribution described as a “bell-shaped curve,”
A normal distribution is described by a normal density curve Any particular normal distribution is completely specified by its mean μ and standard deviation σ