Answer:
0.6856
Step-by-step explanation:
Now; assuming X = no of complaints received in a week
Required:
To find P(77 < X < 120)
Using a Gaussian Normal Distribution (108,
= 20)
Using Z scores:
As a result X = 77 for N(108,20) is approximately equal to to Z = -1.75 for N(0,1)
SO;
Here; X = 77 for a N(108,20) is same to Z = 0.6 for N(0,1)
Now, to determine:
P(-1.75 < Z < 0.6) = P(Z < 0.6) - P( Z < - 1.75)
From the standard normal Z-table:
P(-1.75 < Z < 0.6) = 0.7257 - 0.0401
P(-1.75 < Z < 0.6) = 0.6856