Exam 6: Discrete Probability Distributions

Tabulation of a strike vote showed that 90% of those voting cast their ballot in favour of strike Action. You take a sample of 50 voters. Assume this to be a binomial distribution. What is the mean for this distribution?

An analysis of the grades on the first test in History 101 revealed that they approximate a normal Curve with a mean of 75 and a standard deviation of 8. The instructor wants to award the grade of A To the upper 10 percent of the test grades. What is the dividing point between an A and a B grade?

Two normal distributions are compared. One has a mean of 10 and a standard deviation of 10. The Second normal distribution has a mean of 10 and a standard deviation of 2. Which of the following is True?

Bottomline Ink, a forms management company, fills 100 orders a day with a 2% error rate in the Completed orders. Assume this to be a binomial distribution. What is the mean for this distribution?

Two business major students, in two different sections of economics, were comparing test scores. The following gives the students' scores, class mean, and standard deviation for each section. (i. The student from Section 2 scored better compared to the rest of their section. (ii. The z-score of the student from section 1 is 1.28. (iii) The z-score of the student from section 2 is 1.87.

Replacement times for TV sets are normally distributed with a mean of 8.2 years and a standard Deviation of 1.1 years, (based on data from "Getting Things Fixed," Consumer Reports). (i. The replacement time that separated the top 20% from the bottom 80% is 9.124 years. (ii. The probability that a randomly selected TV will be replaced after more than 10.0 years is 0)0505.

A statistics student receives a grade of 85 on a statistics midterm. If the corresponding z-score Equals +1.5 and the standard deviation equals 7, the average grade on this exam is _______.

The distribution of the annual incomes of a group of middle management employees approximated A normal distribution with a mean of $37,200 and a standard deviation of $800. About 68 percent of The incomes lie between what two incomes?

A loaf of bread is normally distributed with a mean of 22 ounces and a standard deviation of ½ Ounces. (i. The probability that a loaf of bread is < 20 ounces is 0.0. (ii. The probability that a loaf of bread is > 21 ounces is 0.4772. (iii) The probability that a loaf of bread is < 24 ounces is 1.0.

(i. The mean of a normal probability distribution is 60 and the standard deviation is 5. 95.44 percent Of observations lie between 50 and 60. (ii. A z-value of -2.00 indicates that corresponding X value lies to the left of the mean. (iii) One of the properties of the normal curve is that it gets closer to the horizontal axis, but never Touches it. This property of the normal curve is called asymptotic.

What is the distribution with a mean of 0 and a standard deviation of 1 called?

Replacement times for TV sets are normally distributed with a mean of 8.2 years and a standard Deviation of 1.1 years, (based on data from "Getting Things Fixed," Consumer Reports). (i. The replacement time that separated the top 20% from the bottom 80% is 9.124 years. (ii. The probability that a randomly selected TV will be replaced in less than 4.0 years is 0.40.

A major credit card company has determined that customers charge between $100 and $1,100 per Month. Given that the average monthly amount charged is uniformly distributed, what is the Probability that a person charges less than $200 per month?

i. In terms of a formula the standardized value of z is found by z = (X - µ)/σ. ii. The standard normal distribution is a special normal distribution with a mean of 0 and a standard Deviation of 1. iii. A computed z for X values to the right of the mean is positive.

The net profit from a certain investment is normally distributed with a mean of $10,000 and a Standard deviation of $5,000. The probability that the investor will have a net loss is:

A sample of 500 evening students revealed that their annual incomes from employment in industry During the day were normally distributed with a mean income of $30,000 and a standard deviation Of $3,000. (i. 250 students earned more than $30,000. (ii. 314 students earned between $27,000 and $33,000. (iii) 239 students earned between $24,000 and $30,000.

A sample of 500 evening students revealed that their annual incomes were normally distributed With a mean income of $50,000 and a standard deviation of $4,000. How many students earned Less than $45,000?

The employees of Cartwright Manufacturing are awarded efficiency ratings. The distribution of the Ratings approximates a normal distribution. The mean is 400, the standard deviation 50. What is the Area under the normal curve between 400 and 482?

i. Areas within a continuous probability distribution represent probabilities. ii. The Empirical Rule of probability can be applied to the uniform probability distribution. iii. The total area within a continuous probability distribution is equal to 100.

(i. The formula to convert any normal distribution to the standard normal distribution is (ii) The standardized z value measures distance from the mean in units of standard deviation. (iii) The area under a normal curve to the right of a z-score of -1.0 is a proportion of 0.3413.