Questions from Statistics Principles

Q: Give three interpretations for the area under a normal curve.

Give three interpretations for the area under a normal curve.

Q: Explain why P(X < 30) should be reported as

Explain why P(X < 30) should be reported as

Q: Explain why P(X ≤220) should be reported as

Explain why P(X ≤220) should be reported as > 0.9999 if X is a normal random variable with mean 100 and standard deviation 15.

Q: The ACT and SAT are two college entrance exams. The composite

The ACT and SAT are two college entrance exams. The composite score on the ACT is approximately normally distributed with mean 21.1 and standard deviation 5.1. The composite score on the SAT is approx...

Q: A random variable Z that is normally distributed with mean  =

A random variable Z that is normally distributed with mean  = 0 and standard deviation  = 1 is said to have the _____ ______.

Q: A radio station asks its listeners to call in their opinion regarding

A radio station asks its listeners to call in their opinion regarding the use of U.S. forces in peacekeeping missions.

Q: The notation za is the z-score such that the area

The notation za is the z-score such that the area under the standard normal curve to the right of za is______.

Q: If X is a normal random variable with mean 40 and standard

If X is a normal random variable with mean 40 and standard deviation 10 and P(X >45) = 0.3085, then P(X < 35) =_____.

Q: If X is normal random variable with mean 40 and standard deviation

If X is normal random variable with mean 40 and standard deviation 10 and P(X < 38) = 0.4207, then P(X ≤ 38) =____.

Q: Determine the area under the standard normal curve that lies to the

Determine the area under the standard normal curve that lies to the left of (a) z = -2.45 (b) z = -0.43 (c) z = 1.35 (d) z = 3.49