week 4

Suppose that a class contains 15 boys and 30 girls, and that 10 students are to be selected at random for a special assignment. Find the probability that exactly 3 boys will be selected.

Keep in mind that your post must be made by 11:55PM EASTERN time on Wednesday during the week in which a discussion question is posed. I will evaluate your responses to each of these questions using a 0 to 10 point scale, and your contribution to each of the five Discussion Forums will count as 2 percent of the overall course grade for a total of 10 percent.

My evaluation of your post will be based on the extent to which you participated and fostered a positive and effective learning environment--for yourself and others. Participating and sharing are the keys. Naturally, simply copying someone else's post is prohibited. Your post should reflect your understanding of the question posed. In addition to the computations you employed to arrive at your response, your post must contain comments regarding the rationale for the approach you utilized. Simply listing an answer is of no real value in promoting a discussion.

To make a post to this week's Discussion Forum, click on the Counting Isn't Always Easy link, then click Start a New Conversation. In the title block of the dialog box that appears insert your first and last name; compose your post in the message box; and then click Post Message.

week 6

Suppose that the percentage annual return you obtain when you invest a dollar in gold or the stock market is dependent on the general state of the national economy as indicated below. For example, the probability that the economy will be in "boom" state is 0.15. In this case, if you invest in the stock market your return is assumed to be 25%; on the other hand if you invest in gold when the economy is in a "boom" state your return will be minus 30%. Likewise for the other possible states of the economy. Note that the sum of the probabilities has to be 1--and is.

State of economy Probability Market Return Gold Return

Boom 0.15 25% (-30%)

Moderate Growth 0.35 20% (-9%)

Week Growth 0.25 5% 35%

No Growth 0.25 (-14%) 50%

Based on the expected return, would you rather invest your money in the stock market or in gold? Why?

Keep in mind that your post must be made by 11:55PM EASTERN time on Wednesday during the week in which a discussion question is posed. I will evaluate your responses to each of these questions using a 0 to 10 point scale, and your contribution to each of the five Discussion Forums will count as 2 percent of the overall course grade for a total of 10 percent.

My evaluation of your post will be based on the extent to which you participated and fostered a positive and effective learning environment--for yourself and others. Participating and sharing are the keys. Naturally, simply copying someone else's post is prohibited. Your post should reflect your understanding of the question posed. In addition to the computations you employed to arrive at your response, your post must contain comments regarding the rationale for the approach you utilized. Simply listing an answer is of no real value in promoting a discussion.

To make a post to this week's Discussion Forum, click on the Decision Alternatives link, then click Start a New Conversation. In the title block of the dialog box that appears insert your first and last name; compose your post in the message box; and then click Post Message.

week 7

Suppose that the demand for a company’s product in weeks 1, 2, and 3 are each normally distributed and the mean demand during each of these three weeks is 50, 45, and 65, respectively. Suppose the standard deviation of the demand during each of these three weeks is known to be 10, 5, and 15, respectively. It turns out that if we can assume that these three demands are probabilistically independent then the total demand for the three week period is also normally distributed. And, the mean demand for the entire three week period is the sum of the individual means. Likewise, the variance of the demand for the entire three week period is the sum of the individual weekly variances. But be careful! The standard deviation of the demand for the entire 3 week period is not the sum of the individual standard deviations. Square roots don’t work that way!

Now, suppose that the company currently has 180 units in stock, and it will not be receiving any further shipments from its supplier for at least 3 weeks. What is the probability that the company will run out of units?

Keep in mind that your post must be made by 11:55PM EASTERN time on Wednesday during the week in which a discussion question is posed. I will evaluate your responses to each of these questions using a 0 to 10 point scale, and your contribution to each of the five Discussion Forums will count as 2 percent of the overall course grade for a total of 10 percent.

My evaluation of your post will be based on the extent to which you participated and fostered a positive and effective learning environment--for yourself and others. Participating and sharing are the keys. Naturally, simply copying someone else's post is prohibited. Your post should reflect your understanding of the question posed. In addition to the computations you employed to arrive at your response, your post must contain comments regarding the rationale for the approach you utilized. Simply listing an answer is of no real value in promoting a discussion.

To make a post to this week's Discussion Forum, click on the Using the Normal Distribution link, then click Start a New Conversation. In the title block of the dialog box that appears insert your first and last name; compose your post in the message box; and then click Post Message.

week 10

Political polls typically sample randomly from the U.S population to investigate the percentage of voters who favor some candidate or issue. The number of people polled is usually on the order of 1000. Suppose that one such poll asks voters how they feel about the President’s handling of the crisis in the financial markets. The results show that 575 out of the 1280 people polled say they either “approve” or “strongly approve” of the President’s handling of this matter. Based on the sample referenced above, find a 95% confidence interval estimate for the proportion of the entire voter population who “approve” or “strongly approve” of the President’s handling of the crisis in the financial markets.

Now, here’s an interesting twist. If the same sample proportion was found in a sample twice as large—that is, 1150 out of 2560—how would this affect the confidence interval?

Keep in mind that your post must be made by 11:55PM EASTERN time on Wednesday during the week in which a discussion question is posed. I will evaluate your responses to each of these questions using a 0 to 10 point scale, and your contribution to each of the five Discussion Forums will count as 2 percent of the overall course grade for a total of 10 percent.

My evaluation of your post will be based on the extent to which you participated and fostered a positive and effective learning environment--for yourself and others. Participating and sharing are the keys. Naturally, simply copying someone else's post is prohibited. Your post should reflect your understanding of the question posed. In addition to the computations you employed to arrive at your response, your post must contain comments regarding the rationale for the approach you utilized. Simply listing an answer is of no real value in promoting a discussion.

To make a post to this week's Discussion Forum, click on the Build a Confidence Interval Estimate link, then click Start a New Conversation. In the title block of the dialog box that appears insert your first and last name; compose your post in the message box; and then click Post Message.

week 12

A new process for producing synthetic diamonds can be operated at a profitable level only if the average weight of the diamonds produced by the process is greater than 0.5 karat. To evaluate the profitability of the process, a sample of six diamonds was generated using this new process, with recorded weights .46, .61, .52, .48, .57, and .54 karat. Do the six measurements present sufficient evidence to indicate that the average weight of the diamonds produced by the new process is in excess of 0.5 karat? To answer this question conduct an appropriate test of hypothesis using the five step process outlined in our textbook and utilized in the solutions to the Chapter 8 review problems, which can be accessed via the link in the Assignments, Tests & Quizzes sub-section in the weekly lesson that can be found in the Lessons section of our classroom.

Keep in mind that your post must be made by 11:55PM EASTERN time on Wednesday during the week in which a discussion question is posed. I will evaluate your responses to each of these questions using a 0 to 10 point scale, and your contribution to each of the five Discussion Forums will count as 2 percent of the overall course grade for a total of 10 percent.

My evaluation of your post will be based on the extent to which you participated and fostered a positive and effective learning environment--for yourself and others. Participating and sharing are the keys. Naturally, simply copying someone else's post is prohibited. Your post should reflect your understanding of the question posed. In addition to the computations you employed to arrive at your response, your post must contain comments regarding the rationale for the approach you utilized. Simply listing an answer is of no real value in promoting a discussion.

To make a post to this week's Discussion Forum, click on the Testing a Hypothesis link, then click Start a New Conversation. In the title block of the dialog box that appears insert your first and last name; compose your post in the message box; and then click Post Message.

Question 1 of 20

1.0/ 1.0 Points

A variable is classified as ordinal if:

A.we track the variable through a period of time

B.the data arise from continuous measurements

C.there is a natural ordering of categories

D.there is no natural ordering of categories

Question 2 of 20

1.0/ 1.0 Points

Which of the following indicates how many observations fall into various categories?

A.The sample table

B.The tabulation scale

C.The frequency table

D.The Likert scale

Question 3 of 20

1.0/ 1.0 Points

Find the z-score for each student and indicate which one has a better relative position. An Art Major earned a grade of 46 on an exam with f$ar{x}f$ = 50 and s = 5; A Theater Major earned a grade of 70 on an exam with f$ar{x}f$ = 75 and s = 7.

A.The art major has a higher relative position than the theater major.

B.Both students have the same score.

C.The theater major has a higher relative position than the art major.

D.The higher score cannot be determined.

Question 4 of 20

1.0/ 1.0 Points

Which of the following is the graphical analog of a frequency table?

A.The scatterplot

B.The time series plot

C.The histogram

D.The contingency table

Question 5 of 20

1.0/ 1.0 Points

Which of the following are the three most common measures of central location?

A.Mean, variance, and standard deviation

B.Mean, median, and mode

C.Mean, median, and variance

D.Mean, median, and standard deviation

Question 6 of 20

1.0/ 1.0 Points

Suppose that a histogram of a data set is approximately symmetric and "bell shaped". Approximately, what percent of the observations are within three standard deviations of the mean?

A.95%

B.99.7%

C.50%

D.68%

Question 7 of 20

0.0/ 1.0 Points

What type of sampling is being employed if the population is divided into economic classes and a sample is chosen from each economic class to be surveyed?

In A.cluster sampling

B.systematic sampling

C.stratified sampling

D.random sampling

Question 8 of 20

1.0/ 1.0 Points

The length of the box in the boxplot portrays the

A.interquartile range

B.median

C.mean

D.range

Question 9 of 20

1.0/ 1.0 Points

What kind of relationship between x and y is demonstrated by the scatter plot below?

A.A positive linear relationship

B.No linear relationship

C.This is not a scatter plot

D.A negative linear relationship

Question 10 of 20

1.0/ 1.0 Points

A population includes:

A.only households

B.all objects of interest in a particular study

C.only machines

D.only people

Question 11 of 20

1.0/ 1.0 Points

Suppose that a histogram of a data set is approximately symmetric and "bell shaped". Approximately what percent of the observations are within one standard deviation of the mean?

A.99.7%

B.68%

C.95%

D.50%

Question 12 of 20

1.0/ 1.0 Points

The difference between the first and third quartile is called the

A.mid range

B.interquartile range

C.unimodal range

D.interdependent range

Part 2 of 3 - 2.0/ 6.0 Points

Question 13 of 20

0.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

The histogram below represents scores achieved by 250 job applicants on a personality profile.

The histogram below represents scores achieved by 250 job applicants on a personality profile.

Sixty percent of the job applicants scored below what value? Place your answer in the blank. Do not use any stray symbols. For example, 123 would be a legitimate answer.

.30

\

Question 14 of 20

0.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

The following data represent the number of children in a sample of 10 families from Chicago: 4, 2, 1, 1, 5, 3, 0, 1, 0, and 2.

Compute the median number of children. Place your answer, rounded to two decimal places, in the blank. For example, 3.45 would be a legitimate entry. 1.90

Question 15 of 20

0.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

The following data represent the number of children in a sample of 10 families from Chicago: 4, 2, 1, 1, 5, 3, 0, 1, 0, and 2.

Compute the variance of the data. Place your answer, rounded to two decimal places, in the blank. For example, 3.45 would be a legitimate entry. 2.49

Question 16 of 20

1.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

A sample of 150 students at a State University was taken after the final business statistics exam to ask them whether they went partying the weekend before the final or spent the weekend studying, and whether they did well or poorly on the final. The following table contains the result.

Did Well on Exam Did Poorly on Exam

Studying for Exam 60 15

Went Partying 22 53

If the sample is a good representation of the population, what percentage of the students in the population should we expect to spend the weekend studying and do poorly on the final exam? Place your answer in the blank, rounded to 2 decimal places. Do not use a percentage sign (%). For example, 44.44 would be a legitimate answer. 10.00

Question 17 of 20

1.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

The histogram below represents scores achieved by 250 job applicants on a personality profile.

The histogram below represents scores achieved by 250 job applicants on a personality profile.

Seventy percent of the job applicants scored above what value? Place your answer in the blank. Do not use any stray symbols. For example, 123 would be a legitimate answer.

20

Question 18 of 20

0.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

A sample of 150 students at a State University was taken after the final business statistics exam to ask them whether they went partying the weekend before the final or spent the weekend studying, and whether they did well or poorly on the final. The following table contains the result.

Did Well on Exam Did Poorly on Exam

Studying for Exam 60 15

Went Partying 22 53

If the sample is a good representation of the population, what percentage of those who did poorly on the final exam should we expect to have spent the weekend studying? Place your answer in the blank, rounded to 2 decimal places. Do not use a percentage sign (%). For example, 44.44 would be a legitmate answer. 20.00

Part 3 of 3 - 1.0/ 2.0 Points

Question 19 of 20

0.0/ 1.0 Points

A histogram is skewed to the left (or negatively skewed) if it has a single peak and the values of the distribution extend much further to the right of the peak than to the left of the peak.

In

True

False

Answer Key: False

Question 20 of 20

1.0/ 1.0 Points

The number of car insurance policy holders is an example of a discrete random variable

True

False

C.F- distribution

D.t -distribution

Question 9 of 20

1.0/ 1.0 Points

Find the 95% confidence interval for the standard deviation of the lengths of pipes if a sample of 26 pipes has a standard deviation of 10 inches.

A.14.0 < \