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?