The National Assessment of Educational Progress (NAEP) gave a test of basic arithmetic and the ability to apply it in everyday life to a sample of 840 men 21 to 25 years of age. Scores range from 0 to 500; for example, someone with a score of 325 can determine the price of a meal from a menu. The mean score for these 840 young men was x⎯⎯⎯x¯ = 272. We want to estimate the mean score μμ in the population of all young men. Consider the NAEP sample as an SRS from a Normal population with standard deviation σσ = 60.

(a) If we take many samples, the sample mean x⎯⎯⎯x¯ varies from sample to sample according to a Normal distribution with mean equal to the unknown mean score μμ in the population. What is the standard deviation of this sampling distribution?
(b) According to the 99.7 part of the 68-95-99.7 rule, 99.7% of all values of x⎯⎯⎯x¯ fall within _______ on either side of the unknown mean μμ. What is the missing number?
(c) What is the 99.7% confidence interval for the population mean score μμ based on this one sample? Note: Use the 68-95-99.7 rule to find the interval.

Now that you have completed this course in Statistics, please describe a concept covered in the course that you feel might be of assistance to you now or in the future. For example, using charts and graphs to graphically describe data at your job, or using one of the sampling methods discussed at the beginning of the course to generate sample data. Please be specific in explaining how you would use what you have learned in class to your benefit. (Marketing career example)

home / study / math / statistics and probability / statistics and probability questions and answers / Two Machines Are Used For Filling Plastic Bottles With A Net Volume Of 16.0 Ounces. The Filling ...

Question: Two machines are used for filling plastic bottles with a net volume of 16.0 ounces. The filling p...

Edit question

Two machines are used for filling plastic bottles with a net volume of 16.0 ounces. The filling processes can be assumed to be normal. The quality engineering department is concerned that the second machine (Machine 2) is under filling the water bottles compared to the first machine (Machine 1). An experiment to address this concern is performed by taking a random sample from the output of each machine.

16.03   Machine 1
16.04   Machine 1
16.05   Machine 1
16.05   Machine 1
16.02   Machine 1
16.01   Machine 1
15.96   Machine 1
15.98   Machine 1
16.02   Machine 1
15.99   Machine 1
15.99   Machine 2
15.99   Machine 2
15.96   Machine 2
16   Machine 2
15.96   Machine 2
15.95   Machine 2
15.94   Machine 2
16.02   Machine 2
15.97   Machine 2
15.98   Machine 2

Q1

Compute the point estimate for the 95% confidence interval for the difference in mean volume of the bottles filled for Machine 1 versus Machine 2. (Round answer to 2 decimal places).

Q2

Using software or a statistical table, find the critical value for the 95% confidence interval for the difference in mean volume of the bottles filled for Machine 1 versus Machine 2. (Round answer to 2 decimal places).

Q3

Compute the standard error for the 95% confidence interval for the difference in mean volume of the bottles filled for Machine 1 versus Machine 2. (Round answer to 2 decimal places)

Suppose that the heights of male students at a university have a normal distribution with mean = 65 inches and standard deviation = 2.0 inches. A randomly sample of 10 students are selected to make up an intramural basket ball team.

i) What is the mean (mathematical expectation) of xbar?

ii) What is the standard deviation of x bar?

iii) What is the probability that the average height (x bar) of the team will exceed 69 inches?

iv) What is the probability that the average height (x bar) of the team will be between 62 and 70 inches?

This section of the assignment is designed to cultivate skills related to interpreting meaning from quantitative data. As part of a larger study, Speed and Gangestad (1997) collected ratings and nominations on a number of characteristics for 66 fraternity men from their fellow fraternity members. The following paragraph is taken from their results section:

. . . men's romantic popularity significantly correlated with several characteristics: best dressed (r = .48), most physically attractive (r = .47), most outgoing (r = .47), most self- confident (r = .44), best trendsetters (r =.38), funniest (r = .37), most satisfied (r = .32), and most independent (r =.28). Unexpectedly, however, men's potential for financial success did not significantly correlate with romantic popularity (r = .10). (p. 931)

Explain these results as if you were writing to a person who had never had a course in statistics. Specifically:

a) Explain what is meant by correlation coefficient using one of the correlations above as an example.

b) Provide your thoughts on the meaning of the pattern of results. (You could speculate on the meaning of the pattern of results, taking into account the issue of direct causality. You could also indicate what kinds of conclusions could NOT be drawn).  

Given their performance record and based on empirical rule what would be the upper bound of the range of sales values that contains 68% of the monthly sales?

A computer system uses passwords that contain exactly six characters, and each character is 1 of the 26 lowercase letters (a–z) or 26 uppercase letters (A–Z) or 10 integers (0–9). Let Ω denote the set of all possible passwords, and let A and B denote the events that consist of passwords with only letters or only integers, respectively. Determine the number of passwords in each of the following events.

(a) Password contains all lowercase letters given that it contains only letters (b) Password contains at least 1 uppercase letter given that it contains only letters (c) Password contains only even numbers given that it contains all numbers

A national television network took an exit poll of 1460 voters after each had cast a vote in a state gubernatorial election. Of​ them, 680 said they voted for the RepublicanRepublican candidate and 780 said they voted for the DemocraticDemocratic candidate. Treating the sample as a random sample from the population of all​ voters, a 95​% confidence interval for the proportion of all voters voting for the DemocraticDemocratic candidate was (0.509, 0.560). Suppose the same proportions resulted from n=146146 ​(instead of 146​), with counts of 68 and 78​, and that there are only two candidates. Complete parts a and b below.

a. Does a 95% confidence interval using the smaller sample size allow you to predict the​ winner? Explain.

The 95​% confidence interval for the proportion of all voters voting for the DemocraticDemocratic candidate is (____, _____). Now a 95​% confidence interval (does, does not) allow you to predict the​ winner, since this interval (does not include, includes) (0,1, or 0.5).

Problem 12-15 (Algorithmic)

Strassel Investors buys real estate, develops it, and resells it for a profit. A new property is available, and Bud Strassel, the president and owner of Strassel Investors, believes if he purchases and develops this property it can then be sold for $170000. The current property owner has asked for bids and stated that the property will be sold for the highest bid in excess of $100000. Two competitors will be submitting bids for the property. Strassel does not know what the competitors will bid, but he assumes for planning purposes that the amount bid by each competitor will be uniformly distributed between $100000 and $150000.

1. Develop a worksheet that can be used to simulate the bids made by the two competitors. Strassel is considering a bid of $120000 for the property. Using a simulation of 1000 trials, what is the estimate of the probability Strassel will be able to obtain the property using a bid of $120000? Round your answer to 1 decimal place. Enter your answer as a percent.
   
   %
   
2. How much does Strassel need to bid to be assured of obtaining the property?
   
   $  
   
   What is the profit associated with this bid?
   
   $  
   
3. Use the simulation model to compute the profit for each trial of the simulation run. With maximization of profit as Strassel’s objective, use simulation to evaluate Strassel’s bid alternatives of $120000, $145000, or $150000. What is the recommended bid, and what is the expected profit?
   
   A bid of $145000  results in the largest mean profit of $  .

You are hired by Google to research how much people are willing to pay for a new cell phone in US. They are especially interested to know if their new phone, Pixel 3, should be priced similarly to Apple’s iPhone Xs. Google believes that there is a difference between what Android and iPhone users are willing to pay for high-end phones. You are hired to answer this question. Part I: To analyze iPhone users your team randomly selects 16 individuals. See attached data file.

a) Compute sample mean and sample standard deviation for iPhone users

b) Compute 5-number summary for iPhone users

c) Find the 90% confidence interval for the average phone price iPhone users are willing to pay. How do you interpret it?

Use Excel to develop a multiple regression model to predict Cost of Materials by Number of Employees, New Capital Expenditures, Value Added by Manufacture, and End-of-Year Inventories.

Locate the observed value that is in Industrial Group 12 and has 7 employees. Based on the model and the multiple regression output, what is the corresponding residual of this observation? Write your answer as a number, round to 2 decimal places.

Problem 12-01

The management of Brinkley Corporation is interested in using simulation to estimate the profit per unit for a new product. The selling price for the product will be $45 per unit. Probability distributions for the purchase cost, the labor cost, and the transportation cost are estimated as follows:

1. Compute profit per unit for the base-case, worst-case, and best-case scenarios.
   
   Profit per unit for the base-case: $  
   
   Profit per unit for the worst-case: $  
   
   Profit per unit for the best-case: $  
   
2. Construct a simulation model to estimate the mean profit per unit. If required, round your answer to the nearest cent.
   
   Mean profit per unit = $  
   
3. Why is the simulation approach to risk analysis preferable to generating a variety of what-if scenarios?
   
   The input in the box below will not be graded, but may be reviewed and considered by your instructor.
   
   
   
4. Management believes the project may not be sustainable if the profit per unit is less than $5. Use simulation to estimate the probability the profit per unit will be less than $5. If required, round your answer to two decimal places.
   
   %

The following is a cross-tabulation of the variables gender and units (the number of units in which a student has enrolled) from a recent class survey. Number of Units Gender 1 2 3 4 5 female 4 11 60 191 3 male 2 10 28 86 1 Note that χ 2 tests require all expected frequencies to be at least 5. To ensure this you may need to combine columns in a way that makes sense in the context of a test for association. That is, you could combine columns 1 and 2, but not columns 1 and 4. Assuming the data come from randomly-selected Murdoch University students, test for an association between gender and unit load in the Murdoch University student population. If you find an association, describe it.

A researcher wants to study the relationship between salary and gender. She randomly selects 330 ... A researcher wants to study the relationship between salary and gender. She randomly selects 330 individuals and determines their salary and gender. Can the researcher conclude that salary and gender are dependent?

Income Male Female Total

Below $25,000 25 16 41

$25,000-$50,000 47 103 150

$50,000-$75,000 48 32 80

Above $75,000 36 23 59

Total 156 174 330

Step 1 of 8: State the null and alternative hypothesis. Step 2 of 8: Find the expected value for the number of men with an income below $25,000. Round your answer to one decimal place. Step 3 of 8: Find the expected value for the number of men with an income $50,000-$75,000. Round your answer to one decimal place. Step 4 of 8: Find the value of the test statistic. Round your answer to three decimal places. Step 5 of 8: Find the degrees of freedom associated with the test statistic for this problem. Step 6 of 8: Find the critical value of the test at the 0.01 level of significance. Round your answer to three decimal places. Step 7 of 8: Make the decision to reject or fail to reject the null hypothesis at the 0.01 level of significance. Step 8 of 8: State the conclusion of the hypothesis test at the 0.01 level of significance.