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Normal distribution properties

To access the normal distribution properties, open "descriptive statistics/details"
Propriétés loi normale
In addition to “the universality” of normal distribution, it is also very practical to characterize. The normal distribution equation is:
Only two parameters completely characterizing the distribution:
  • average
  • standard deviation
If these two parameters are known, then all the characteristics of the observed distribution are fully known. This is what a normal distribution looks like with an average of 0 and standard deviation of 1:
Loi normale1
From now on the normal distribution average and standard deviation will be noted. This distribution can be perfectly defined since the two parameters are known: average and standard deviation.
To understand the normal distribution well it is good to know the following figures:
  • 68.27% of the actual values are located at + 1 of the average
  • 95.45% of the actual values are located at + 2 of the average
  • 99.73% of the actual values are located at + 3 of the average
Loi normale2