Percentage of the student body exists at least 21 years old exists 50%.
A continuous probability distribution for a real-valued random variable in statistics is known as a normal distribution or Gaussian distribution.
As one moves away from the center, values start to taper off and the majority of values are concentrated in this area. In a normal distribution, the mean, mode, and median are identical measures of central tendency.
When given a normal or Symmetric distribution, the mean of the distribution exists at the center with 0.5 or 50% of the distribution to either side (right and left) of the distribution.
Therefore, if the mean = 21 ; then the percentage of student body with at least 21 years is the percentage to the left of the distribution, which exists 50%.
P(x ≤ 21) = 0.5 = 50%
Therefore, 50 percentage of the student body exists at least 21 years old
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