In probability theory a normal distribution is a kind of probability distribution with a set value of random variables. The normal distribution formula is: {formula} Normal distributions are valuable in statistical analysis and is used a lot in trading to set values on random variables of future distributions that are not known. Normal distribution states that under market conditions over many average samples of data of random variables with set boundaries of movement the distribution of price data is thought to converge back into a normal distribution of the historical mean as the quantity of the sample size grows. ... (full story)