Color-blindness is any abnormality of the color vision system that causes a person to see colors differently than most people or to have difficulty...

1.Color-blindness is any abnormality of the color vision system that causes a person to see colors differently than most people or to have difficulty distinguishing among certain colors (www.visionrx.xom).

Color-blindness is gender-based, with the majority of sufferers being males.

Roughly 8% of white males have some form of color-blindness, while the incidence among white females is only 1%.

A random sample of 20 white males and 40 white females was chosen.

Let X be the number of males (out of the 20) who are color-blind.

Let Y be the number of females (out of the 40) who are color-blind.

Let Z be the total number of color-blind individuals in the sample (males and females together).

Which of the following is true regarding the random variables X and Y?

• a.Both X and Y can be well-approximated by normal random variables.
• B.Only X can be well-approximated by a normal random variable.
• C.Only Y can be well-approximated by a normal random variable.
• D.Neither X nor Y can be well-approximated by a normal random variable.

2.Suppose the scores on an exam are normally distributed with a mean μ = 75 points, and standard deviation σ = 8 points.

What is the exam score for an exam whose z-score is 1.25?

• a.65
• b.75
• c.85
• d.0.8944
• e.0.1056