Question

Sugar canes have lengths X that are normally distributed with mean 365.45 cm and standard deviation 4.9 cm what is the probability of the length of a randomly selected Cane being between 360 and 370 cm

Answer 1

Answer:

The probability of the length of a randomly selected Cane being between 360 and 370 cm  P(360 ≤X≤370)    = 0.6851

Step-by-step explanation:

step(i):-

Let 'X' be the random Normal variable

mean of the Population = 365.45

Standard deviation of the population = 4.9 cm

Let X₁ =  360

$Z= \frac{x-mean}{S.D}= \frac{360-365.45}{4.9}$

Z₁ = -1.112

Let X₂ =  370

$Z= \frac{x-mean}{S.D}= \frac{370-365.45}{4.9}$

Z₂ = 0.911

Step(ii):-

The probability of the length of a randomly selected Cane being between 360 and 370 cm

                  P(x₁≤x≤x₂) =    P(z₁≤Z≤z₂)

               P(360 ≤X≤370)   =    P(-1.11≤Z≤0.911)

                                     =    P(Z≤0.911)-P(Z≤-1.11)

                                     =   0.5 +A(0.911) - (0.5-A(1.11)

                                       =    0.5 +A(0.911) - 0.5+A(1.11)

                                      =     A(0.911) + A(1.11)

                                    =    0.3186 + 0.3665

                                     = 0.6851

The probability of the length of a randomly selected Cane being between 360 and 370 cm  P(360 ≤X≤370)    = 0.6851