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The weight of an organ in adult males has a bell shaped distribution with a mean of 325 grams and a standard deviation of 50 grams. (A) about 99.7% of organs will be between what weights? (B) what percentage of organs weighs between 275 grams and 375? (C) what percentage of organs weighs between 275 grams and 425 grams?

Respuesta :

Answer:

A)

The number of weights of an organ in adult males = 374.85

B)

The percentage of organs weighs between 275 grams and 375

P(275≤x≤375) = 0.6826 = 68%

C)

The percentage of organs weighs between 275 grams and 425

P(275≤x≤375) = 0.8185 = 82%

Step-by-step explanation:

A)

Step(i):-

Given mean of the normal distribution = 325 grams

Given standard deviation of the normal distribution = 50 grams

Given Z- score = 99.7% = 0.997

[tex]Z = \frac{x-mean}{S.D} = \frac{x-325}{50}[/tex]

[tex]0.997 = \frac{x-325}{50}[/tex]

Cross multiplication , we get

[tex]0.997 X 50= x-325[/tex]

x - 325 = 49.85

x = 325 + 49.85

x = 374.85

The number of weights of an organ in adult males = 374.85

Step(ii):-

B)

Let X₁ = 275 grams

[tex]Z_{1} = \frac{x_{1} -mean}{S.D} = \frac{275-325}{50} = -1[/tex]

Let X₂ = 375 grams

[tex]Z_{2} = \frac{x_{2} -mean}{S.D} = \frac{375-325}{50} = 1[/tex]

The probability of organs weighs between 275 grams and 375

P(275≤x≤375) = P(-1≤Z≤1)

                       = P(Z≤1)- P(Z≤-1)

                      =  0.5 + A(1) - ( 0.5 - A(-1))

                     = A(1) + A(-1)

                    = 2 A(1)

                    = 2 × 0.3413

                    = 0.6826

The percentage of organs weighs between 275 grams and 375

P(275≤x≤375) = 0.6826 = 68%

C)

Let X₁ = 275 grams

[tex]Z_{1} = \frac{x_{1} -mean}{S.D} = \frac{275-325}{50} = -1[/tex]

Let X₂ = 425 grams

[tex]Z_{2} = \frac{x_{2} -mean}{S.D} = \frac{425-325}{50} = 2[/tex]

The probability of organs weighs between 275 grams and 425

P(275≤x≤425) = P(-1≤Z≤2)

                       = P(Z≤2)- P(Z≤-1)

                      =  0.5 + A(2) - ( 0.5 - A(-1))

                     = A(2) + A(-1)

                    = A(2) + A(1)       (∵A(-1) =A(1)

                    = 0.4772 + 0.3413

                    = 0.8185

The percentage of organs weighs between 275 grams and 425

P(275≤x≤375) = 0.8185 = 82%