Probability based on Z score for a normal variable

Given that z is a standard normal random variable and that the area to the right of z is 0.1949, then the value of z must be
A) 0.51
B) -0.51
C) 0.86
D) -0.86

Your high school graduating class had 564 members. Thirty-three percent of these are expected to attend college. The probability that less than 160 will attend college is
A) 0.1580
B) 0.4900
C) 0.0090
D) 0.0832

The sampling distribution of the mean will have the same standard deviation as the original population from which the samples were drawn.
True
False

In a given year, the average annual salary of a NFL football player was $189,000 with a standard deviation of $20,500. If a sample of 50 players was taken, then probability that the sample mean will be $192,000 or more is
A) 0.6970
B) 0.3485
C) 0.1515
D) 0.0398

Solution Summary

This solution gives the step by step method for computing probabilities based on Z score.

A normal population has an average of 80 and a standard deviation of 14.0.
Calculate the probability of a value between 75.0 and 90.0.
Calculate the probability of a value of 75.0 or less.
Calculate the probability of a value between 55.0 and 70.0.

1. Given that z is a standard normal random variable, compute the following probabilities.
a. p (z = 2.0)
b. p (z ≥ 1.4)
c. p (-1.0 < z < 0.5)
d. p (1.0 < z < 1.2)
2. The time needed to drive from city A to city B is normally distributed with a mean of 180 minutes and standard deviation of 20 minutes.
a. Wha

A normal distribution has a mean of u= 40 and o=10. if a vertical line is drawn through the distribution at x= 55, what proportion of the scores on the right side of the line?
A normal distribution has a u= 80 and o= 10. what is the probability of randomly selecting a score greater than 90 from this distribution?
A normal

I need help with some practice problems that were given to us, to help prepare for a quiz next week. Please provide detailed steps as to how you came by your answer (include any notes, calculations, or anything that may be pertinent to the solution).
As always, your help would be greatly appreciated!
Thanks,
E

1. For a standardized normal distribution calculate the following probabilities
a. P(0.00 < z < or equal to 2.33)
b. P( -1.00 < z < or equal to 1.00)
c. P( 1.78 < z < 2.34).
2. A random variable is normally distributed with mean of 25 and standard deviation of 5. If an observation is randomly selected
a. what val

For questions 1-5 use the random variable X with values x = 2, 3, 4, 5 or 6 with P(x) = 0.05x.
1. Determine P (x = 4).
a. 0.05 b. 0.10 c. 0.15 d. 0.20
2. Find P (x >= 4).
a. 0.60 b. 0.45 c. 0.75 d. 0.55
3. What is P (2 < x <= 5)?
a. 0.70

A drug company believes that the annual demand for a drug will follow a normal random variable with a mean of 900 pounds and a standard deviation of 60 pounds. If the company produces 1000 pounds of the drug, what is the chance (rounded to the nearest hundredth) that it will run out of the drug? Assume that the only way to meet

For any normal distribution, what is the probability of selecting a score greater than the mean?
A. 50%
B. 25%
C. 34.13%
D. cannot be determined without additional information