The red blood cell counts (in millions of cells per microliter) for a population of adult males can be approximated by a normal distribution, with a mean of 5.8 million cells per microliter and a standard deviation of 0.4 million cells per microliter.

(a) What is the minimum red blood cell count that can be in the top 21 %of counts?

(b) What is the maximum red blood cell count that can be in the bottom 11 %of counts?

Using the normal distribution, we have that the blood counts are:

a) 6.12 million cells per microliter.

b) 4.81 million cells per microliter.

In a normal distribution with mean and standard deviation , the z-score of a measure X is given by:

In this problem:

Item a:

This is the 100 - 21 = 79th percentile, which is X when Z has a p-value of 0.79, so X when Z = 0.807.

Hence, 6.12 million cells per microliter.

Item b:

This is the 11th percentile, which is X when Z has a p-value of 0.11, so X when Z = -1.227.

Hence, 4.81 million cells per microliter.

A similar problem is given at link

(a) The minimum red blood cell count that can be in the top 21% of counts is 6.1.

(b) The maximum red blood cell count that can be in the bottom 11% of counts is 5.3.

Step-by-step explanation:

The random variable X can be defined as the number of red blood cells in adult males.

The random variable X can be approximated by a normal distribution.

The mean number of red blood cells is, μ = 5.8 million cells per micro liter.

The standard deviation of red blood cells is, σ = 0.4 million cells per micro liter.

(a)

Compute the value of x such that P (X > x) = 0.21 as follows:

   P (X > x) = 0.21

⇒ P (Z > z) = 0.21

The value of z is, 0.81.

*Use a z-table.

Compute the value of x as follows:

Thus, the minimum red blood cell count that can be in the top 21% of counts is 6.1.

(b)

Compute the value of x such that P (X < x) = 0.11 as follows:

   P (X < x) = 0.11

⇒ P (Z < z) = 0.11

The value of z is, -1.23.

*Use a z-table.

Compute the value of x as follows:

Thus, the maximum red blood cell count that can be in the bottom 11% of counts is 5.3.

2 x^2 -3x+p

sum of roots = 3/2

let other root be x

3+ x = 3/2

x= 3/2 - 3 = -3/2

product of roots = p/2

3× -3/2 = p/2

-9 = p

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i use my brain for prombles like this maybe you could try it

step-by-step explanation: