A business school claims that students who complete a 3-month typing course can type a mean of more than 1200 words an hour. A random sample of 25 students who completed this course typed a mean of 1163 words an hour, with a sample standard deviation of 87 words. Assume that typing speeds for all students who complete this course have an approximately normal distribution. (a) Using the critical value method and a significance level of 1%, is there evidence to support the business school’s claim? (b) What would a Type II error be in this case?

A peony plant with red petals was crossed with another plant having streaky petals. A geneticist states that 70% of the offspring resulting from this cross will have red flowers. To test this, 80 seeds from this cross were collected and germinated and 46 plants had red petals. (a) Is there sufficient evidence at the 0.02 significance level to indicate the proportion of the hybrid plants with red petals differs from 70%? Use the P-value method in your test. (b) What would a Type I error be in this case?

Suppose John is a high school statistics teacher who believes that eating candy improves focus, which leads to higher test scores. Immediately after giving the most recent test, he surveyed each of the 35 students in his class and asked them how many individual candies they ate that week. He then matched each student's test grade with his or her survey response. After compiling the data, he used the number of candies eaten to predict each student's test score. He found the least-squares regression line to be ?̂=2.8?+86y^=2.8x+86. He also calculated that the value of ?r, the correlation coefficient, was 0.54.

Which of the choices identifies the correct value of the coefficient of determination, ?2R2, and gives a correct interpretation of its meaning?

?2=0.54R2=0.54, meaning 54% of the total variation in test scores can be explained by the least‑squares regression line.

?2=0.2916R2=0.2916, meaning 29.16% of the total variation in test scores can be explained by the least‑squares regression line.

?2=0.54R2=0.54, meaning 54% of the total variation in the number of candies eaten can be explained by the least‑squares regression line.

?2=0.7348R2=0.7348, meaning 73.48% of the total variation in test scores can be explained by the least‑squares regression line.

?2=0.2916R2=0.2916, meaning 29.16% of the total variation in the number of candies eaten can be explained by the least‑squares regression line.

Governmental Taking of Private Property

Certain religious organizations propose to build a private independent middle

school in a run-down neighborhood in Philadelphia, Pennsylvania. The religious

organizations asked the Redevelopment Authority of the City of Philadelphia to acquire

specific land for the project and sell it to them for a nominal price. The land included a

house on North Eighth Street owned by Mary Smith, whose daughter Veronica lived

there with her family. The Authority offered Smith $12,000 for the house and initiated a

taking of the property. Smith filed a suit in state court against the Authority, admitting

that the house was a “substandard structure in a blighted area,” but arguing that the

taking was unconstitutional because its beneficiary was private. The Authority asserted

that the taking would serve a public purpose---education.

On what basis can the

government take private property? What is the significance of Smith’s argument

(i.e., private beneficiary) and the Authority’s argument (i.e., it will serve a public

purpose)?

Pedro is a primary school teacher who raises pigs for additional income. He must decide how to feed his pigs and is considering combining two brands, A and B. Both brands are available from local suppliers. Pedro wants to feed his pigs at minimal cost, but ensuring that they eat the minimum calorie and vitamin requirements. The cost, calorie and vitamin content for the two brands are in the following table.

Each pig requires, per day, at least 8000 calories and at least 700 units of vitamin. Also, since brand A has an ingredient that is toxic if ingested in large quantities, no more than a third of the total weight of daily intake can be from brand A.
a) (15 points) Clearly define the decision variables and formulate a PL model for this problem.
b) (10 points) Using some linear programming software, solve your model formulated in the subsection
previous. Clearly specify the optimal values of the decision variables as well as that of the function
objective. Include a screenshot of the software output.

Really Cheap Used Computers, Inc. is an online seller of old school computers. The organization’s e-commerce Web

site runs on a Linux server. The server is located at the organization’s local office in Boston, Massachusetts. The

company has experienced tremendous growth and has hired you as the new security analyst. You access the server

and find that there are no layers of security other than the passwords set for user accounts.

Discuss at least three layers of access control that can be put in place on this server to create a more secure

environment. Rationalize whether the given scenario represents discretionary access control (DAC) or mandatoryaccess control (MAC).

Participate in this discussion by engaging in a meaningful debate regarding your choices of the three layers of

access control in Linux. You must defend your choices with a valid rationale. Summarize your thoughts in a Word

document and submit it to your instructor

Should be 1-2 pages

Self-Assessment Checklist



I identified at least three layers of access controls that can be used to create a secure Linux server

environment.



I determined whether the given scenario represented DAC or MAC.



I engaged in a discussion of the assigned topic with at least two of my peers.



I supported my arguments with data and factual information.



I compared and contrasted my position with the perspectives offered by peers.



I raised questions and solicited peer and instructor input on the topics discussed.



I articulated my position clearly and logically.



I followed the submission requireme

Based upon extensive data from a national high school educational testing​ program, the mean score of national test scores for mathematics was found to be 605 and the standard deviation of national test scores for mathematics was found to be 98 points. What is the probability that a random sample of 196 students will have a mean score of more than 610? Less than 591​?

a) The probability that a random sample of 196 students will have a mean score of more than 610 is ?

b) The probability that a random sample of 196 students will have a mean score of less than 591 is ?

"Freshman 15": Fact or Fantasy? BOSTON Along with all of the typical "back-to-school" hype about lunch boxes and school buses, each September is typically greeted with media reports and advice about the "freshman 15," which is the popular name given to the phenomenon of first-year college students gaining 15 pounds during their freshman year. But does this 15 pound weight gain actually occur, or is it simply a myth? Carole Nhu'y Hodge, Linda Jackson, and Linda Sullivan are Michigan State University researchers who conducted their own investigation. They studied 61 Michigan State female students who took an introductory psychology course. The volunteers, who were given extra credit for participation in the experiment, were weighed at the beginning of their freshman year and at a point in time six month later. Among their findings reported in Psychology of Women Quarterly : "Body weight at the beginning of the first college year (Time 1) was compared with weight approximately 6 months later (Time 2). Average weight at Time 2, 131.45 lb (59.62 kg), was no different from average weight at Time 1, 130.57 lb (59.23 kg)." They also state that "Our findings suggest it (the 15-lb weight gain)is fantasy, although additional research is needed before drawing firm conclusions."

The Assignment:

Answer the following:

1. What do the researchers infer when they say that there is "no difference" between the mean weight at Time 1 (130.57 lb) and the mean weight at Time 2 (131.45lb), when there is an apparent difference of 0.88-lb?
2. What are the limitations of this particular study? That is, if the sample data are used to make inferences about a population, identify the specific population in question.
3. Identify any aspects of the experiment that could potentially threaten the validity of the results.
4. Identify a possible null hypothesis and alternative hypothesis for this experiment.
5. Your submission is to be a well-written grammatically correct response.

A researcher wants to determine whether high school students who attend an SAT preparation course score significantly different on the SAT than students who do not attend the preparation course. For those who do not attend the course, the population mean is 1050 (μ = 1050). The 16 students who attend the preparation course average 1150 on the SAT, with a sample standard deviation of 300. On the basis of these data, can the researcher conclude that the preparation course has a significant difference on SAT scores? Set alpha equal to .05.

Q1: The appropriate statistical procedure for this example would be a

A. z-test

B. t-test

Q2: The most appropriate null hypothesis (in words) would be

A. There is no statistical difference in SAT scores when comparing students who took the SAT prep course with the general population of students who did not take the SAT prep course.

B. There is a statistical difference in SAT scores when comparing students who took the SAT prep course with the general population of students who did not take the SAT prep course.

C. The students who took the SAT prep course did not score significantly higher on the SAT when compared to the general population of students who did not take the SAT prep course.

D. The students who took the SAT prep course did score significantly higher on the SAT when compared to the general population of students who did not take the SAT prep course.

Q3: The most appropriate null hypothesis (in symbols) would be

A. μSATprep = 1050

B. μSATprep = 1150

C. μSATprep  1050

D. μSATprep  1050

Q4: Based on your evaluation of the null in and your conclusion, as a researcher you would be more concerned with a

A. Type I statistical error

B. Type II statistical error

Calculate the 99% confidence interval. Steps:

Q5: The mean you will use for this calculation is

A. 1050

B. 1150

Q6: What is the new critical value you will use for this calculation?

Q7: As you know, two values will be required to complete the following equation:

__________    __________

Q8: Which of the following is a more accurate interpretation of the confidence interval you just computed?

A. We are 99% confident that the scores fall in the interval _____ to _____.

B. We are 99% confident that the average score on the SAT by the students who took the prep course falls in the interval _____ to _____.

C. We are 99% confident that the example above has correct values.

D. We are 99% confident that the difference in SAT scores between the students who took the prep course and the students who did not falls in the interval _____ to _____.

Dean Parmalee wished to know if the year-end grades assigned to Wright State University Medical School students are predictive of their second-year medical board scores. The following table shows, for 89 students, the year-end score (AVG, in percent of 100) and the score on the second year medical board (BOARD) examination (data: medscores.mtw).

a) Create scatterplots of BOARD vs. AVG. Assess the nature of the relationship of these variables.

2. Give the estimates of the coefficients of your model.

3. Interpret the Estimated intercept and slope?

4. What is the value of R-square? Interpret it.

5. Are there any outliers or influential observations?

6. Give the predicted BOARD score for an individual with an 85 average. Interpret it.

7. Assess the fit of the model and interpret.

8. Explain why this model is not appropriate for someone with AVG value of 60.0.

9. Use the regression model to give 95% mean and individual prediction intervals for AVG score of 95.73 and 94.03. Make a graph showing the 95% confidence bands for the mean and the 95% prediction intervals.

type in will be best：）