Scores on the Mathematics section of the SAT Reasoning Test form a normal distribution with a mean of μ = 500 and a standard deviation of 100. What is the minimum score necessary to be in the top 10% of the distribution?

Respuesta :

Answer:

The minimum score necessary to be in the top 10% of the distribution is 628.

Step-by-step explanation:

Given that a normal distribution has a mean of μ = 500 and a standard deviation = σ= 100

The Significance level  for this test = 10 % = 0.1

For one tailed test ∝= 0.1 the value of Z∝= ±1.28

Since it a normal distribution the test statistic used is

Z= X= u / σ/√n   ( taking n= 1)

1.28 = X- 500/100/√1

128 + 500 = X

or X = 628

The minimum score necessary to be in the top 10% of the distribution is 628.