Answer:
The probability of of a randomly chosen student being exactly 21 years old.
= 1.293
Step-by-step explanation:
<u><em>Step(i):-</em></u>
<em>Given Population size n = 500</em>
<em>Mean of the Population = 20 years and 6 months</em>
<em> = </em>
<em></em>
<em>Standard deviation of the Population = 2 years</em>
Let 'X' be the range of ages of the students on campus follows a normal distribution
Let x =21


<em>The probability of a randomly chosen student being exactly 21 years old.</em>
<em>P( Z≤21) = 0.5 + A( 0.2) </em>
= 0.5 +0.793
= 1.293
For A B and C, you just plug in the given number
A

B

C

And for D, you set the equation to 26 and solve for n

I had to use x instead of n, but for D n=7. :)
-(7+8/100)
= -(7+4/50)
= -(7+2/25)
= -177/25
Yes, it will always be a rational number. I'll expound on this by defining what a rational number is. It is any number that can be expressed as a fraction. Otherwise, it is called an irrational number with a non-terminating decimal expansion. So, although 1/3 has a non-terminating decimal expansion because it is equal to 0.33333333...., it is still a rational number because it can be expressed into a fraction.