Question

In: Statistics and Probability

The amount of factor X is human blood is believed to follow a normal curve with...

The amount of factor X is human blood is believed to follow a normal curve with a mean of 4500 units and a standard deviation of 1000 units. What is the range of test scores that will cover the middle 75% of the population?

Expert Solution

Given that,

mean = = 4500

standard deviation = =1000

middle 75% of score is

P(-z < Z < z) = 0.75

P(Z < z) - P(Z < -z) = 0.75

2 P(Z < z) - 1 = 0.75

2 P(Z < z) = 1 + 0.75 = 1.75

P(Z < z) = 1.75 / 2 = 0.875

P(Z <1.15 ) = 0.875

z ± 1.15 using z table

Using z-score formula

x= z * +

x= -1.15 *1000+4500

x= 3350

z = 1.15

Using z-score formula

x= z * +

x= 1.15 *1000+4500

x= 5650

range= 3350 to 5650

orchestra answered 2 years ago

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