Answer:
a = -2.57 and b = 2.57
Step-by-step explanation:
Explanation:
Given mean of the Population = 212
Standard deviation of the Population = 122
Let  X be the random variable of the Normal distribution
[tex]Z = \frac{x-mean}{S.D}[/tex]
Given P( a ≤ z ≤b) = 0.99
 put a=-b
     P( -b ≤ z ≤b) = 0.99
  ⇒   |A( b) - A( -b)| =0.99
  ⇒   | A( b) + A( b)| =0.99 Â
  ⇒    2 |A (b)| = 0.99
   ⇒   | A(b)| = 0.495
From normal table find value in areas
     b = 2.57 ( see in  normal table)
     Given a =-b
          a = - 2.57
