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#HOW TO PUT A BELL CURVE ON A HISTOGRAM IN EXCEL 2016 SOFTWARE#
Statistical software (such as SPSS) can be used to check if your dataset is normally distributed by calculating the three measures of central tendency. How can I check if my data follows a normal distribution? This means there is a 99.7% probability of randomly selecting a score between -3 and +3 standard deviations from the mean. This means there is a 95% probability of randomly selecting a score between -2 and +2 standard deviations from the mean.ĩ9.7% of data will fall within three standard deviations from the mean.
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This means there is a 68% probability of randomly selecting a score between -1 and +1 standard deviations from the mean.ĩ5% of the values fall within two standard deviations from the mean. The empirical rule allows researchers to calculate the probability of randomly obtaining a score from a normal distribution.Ħ8% of data falls within the first standard deviation from the mean. If the data values in a normal distribution are converted to standard score (z-score) in a standard normal distribution the empirical rule describes the percentage of the data that fall within specific numbers of standard deviations (σ) from the mean (μ) for bell-shaped curves. The empirical rule is often referred to as the three-sigma rule or the 68-95-99.7 rule. The empirical rule in statistics allows researchers to determine the proportion of values that fall within certain distances from the mean. Probability and the normal curve: What is the empirical rule formula?
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