Answer:
The probability that a call lasts less than 4 minutes
P(X<4) = P(Z<-1.25) = 0.1056
Step-by-step explanation:
Step(i):-
Given mean of the population = 6.5 minutes
Given standard deviation of the Population = 2 minutes
Let 'X' be the random variable in normal distribution
Given X = 4
[tex]Z= \frac{x-mean}{S.D} = \frac{4-6.5}{2} = -1.25[/tex]
Step(ii):-
The probability that a call lasts less than 4 minutes
P(X<4) = P(Z<-1.25)
= 1-P(z>1.25)
= 1 - ( 0.5 +A(1.25)
= 1-0.5 - A(1.25)
= 0.5 - 0.3944 ( from normal table)
= 0.1056
Final answer:-
The probability that a call lasts less than 4 minutes
P(X<4) = P(Z<-1.25) = 0.1056
