Mathematics Homework Help

PH 302 California State University San Marcos Math Problem Set

 

The following scenario is the information necessary to answer questions 1-12.

SCENARIO: 1236 Marine recruits entered training during one week in June. Marine recruits are medically examined and must be injury and illness free before beginning training. 112 refused to participate in a study to follow them during 12 weeks of training for the development of stress fractures. All recruits who consented to participate (everyone but those who refused to participate) were successfully followed for all 12 weeks. During the 12 weeks, 55 recruits developed a stress fracture. Of these 55, 26 subjects suffered stress fractures in the first 6 weeks and each of these 26 were fully recovered within 5 weeks. The shortest recovery time among those suffering stress fractures after week 6 was 7.5 weeks. At the beginning of training it was determined that 20% of participants were classified as being in “poor physical fitness.” The remaining recruits were in “better than poor physical fitness.” The incidence of stress fractures in the poor physical fitness group was 9.8%.

Hint: you may want to “draw” a timeline of the 12 week follow-up period to better understand prevalence and incidence of stress fractures over that time period.

  1. What is the size of the study group?
  2. What is the stress fracture incidence?
  3. What is the stress fractures incidence rate?
  4. What is absolute risk of stress fracture during training?
  5. What is the prevalence rate of stress fractures at the beginning of training (1st day of training)?
  6. What is the prevalence rate of stress fractures at the end of training?
  7. Create a 2X2 table for stress fracture given physical fitness group?
  8. What is the incidence rate of stress fractures among the better than poor physically fit recruits?
  9. What PERCENT of stress fractures in the poor fit group could be reduced by increasing fitness to better than poor?
  10. Among all recruits, what percent of stress fractures could be reduced by increasing fitness to better than poor?
  11. What is the relative risk for stress fracture if a recruit is in poor fitness?
  12. What is the interpretation of this relative risk?

The following scenario is the information necessary to answer questions 13-19.

SCENARIO: In National City they have begun a new initiative to reduce the effects of risky sexual behavior among the 150,000 residents. 33% of the population is between 1-14 years old, 20%, 15-21 years old, 30%, 22-40 years old, and 17% older than 41. Chlamydia is the most common sexually transmitted disease with a duration that can vary from a few days to many months. Before the program began, 145, 15-21 year olds were diagnosed with chlamydia in 1996. 145 people aged 22-40 were also diagnosed with chlamydia in the same year. 16 people aged 15-40 died from chlamydia in 1996. A total of 345 people of all ages were diagnosed with chlamydia during 1996.

In 1997 a sample of 3500 National City residents were recruited into a study . Each subject was asked about their current sexual behavior and each person’s medical record was reviewed for diagnosis of chlamydia at the time of enrollment in 1997. 37 individuals from the sample had documentation of chlamydia of which 35% claimed to never use condoms during the same time period. Condom use in the entire sample was reported by 62% of the subjects.

13. What was the crude prevalence rate for chlamydia for 1996 in National City?

14. What was the age-specific chlamydia rate for 15-21 year olds in National City in 1996? For 22-40 year olds?

15. What age group seems to have the highest problem with chlamydia, 15-21 or 22-40?

16. What is the chlamydia case fatality rate for 15-40 year olds in 1996?

17. Fill in the 2X2 table for chlamydia vs condom use in the sample in 1997?

18. Does condom use appear to be associated with chlamydia diagnosis in the 1997 study? Yes or no.

19. Was there a positive or negative association of condom use with chlamydia diagnosis?

USE THIS DOCUMENT FOR SUBMITTING ANSWERS: (I attached a file for the answers)

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PUBH 8500 Walden Assumptions of Linearity Sampling independence Normality & Homoscedasticity Paper

 

Assignment: Assessment

The testing of assumptions, recognition of limitations, and proper use of diagnostics are all necessary elements in the use of multiple linear regression for public health research. All of these elements allow biostatisticians to better assess the results of multiple linear regression models.

For this Assignment, you test that assumptions for multiple linear regression have been met, use SPSS to create a multiple linear regression, evaluate results to determine whether the model is appropriate, and finally interpret the relationships uncovered through this statistical test between the independent and dependent variables. Use the Week 4 Dataset (SPSS document) from the Learning Resources area to complete this assignment.

The Assignment
  1. Explain the assumptions of Linearity, Sampling independence, Normality, and Homoscedasticity (or equal variance). (30 points)
    1. How would you test whether these have been met? (Note: for the exam you do not need to test these assumptions)
    2. Using SPSS, test the assumption of Linearity between the independent and dependent variables.
    3. Using SPSS, test the assumption of Normality for the dependent variable.
  2. Conduct a multiple linear regression using SPSS. Provide relevant SPSS output and assess the statistical significance of the effects of mother’s Age, BMI, and Coffee (Cups per Day) on Birth weight. (30 points)
  3. Explain the practical implications of your finding. Include a reference to the R square of the model in your discussion. (20 points)
  4. Discuss whether or not there is interaction (effect modification) first between Age and BMI and second between BMI and Coffee. (20 points)

Mathematics Homework Help

Standard Deviation Questionnaire

 

Find P(Z ≥ 1.8). Round answer to 4 decimal places. Answer:

Question 2 (1 point)

Question 2 options:

Find P(-1.96 ≤ Z ≤ 1.96). Round answer to 2 decimal places. Answer:

Question 3 (1 point)

Saved

Question 3 options:

A dishwasher has a mean life of 12 years with an estimated standard deviation of 1.25 years (“Appliance life expectancy,” 2013). Assume the life of a dishwasher is normally distributed. Find the number of years that the bottom 25% of dishwasher would last. Round answer to 2 decimal places. Answer:

Question 4 (1 point)

Find the probability that

χχ

Shaded graph that extends from 0 to 8.5 shaded up to 5.  X axis goes from 0 to 10 and y-axis is labeled with 1/8

Question 4 options:

0.438

0.625

0.125

0.5

Question 5 (1 point)

The manufacturer of a new compact car claims the miles per gallon (mpg) for the gasoline consumption is mound-shaped and symmetric with a mean of 24.6 mpg and a standard deviation of 9.5 mpg. If 30 such cars are tested, what is the probability the average mpg achieved by these 30 cars will be greater than 28?

Answer: ___ Round your answer to 4 decimal places as necessary. For example, 0.1357 would be a legitimate entry. Make sure you include the 0 before the decimal.

___

Question 5 options:

Question 6 (1 point)

The average lifetime of a set of tires is three years. The manufacturer will replace any set of tires failing within two years of the date of purchase. The lifetime of these tires is known to follow an exponential distribution. What is the probability that the tires will fail within two years of the date of purchase?

Question 6 options:

0.8647

0.2212

0.4866

0.9997

Question 7 (1 point)

The average lifetime of a certain new cell phone is three years. The manufacturer will replace any cell phone failing within two years of the date of purchase. The lifetime of these cell phones is known to follow an exponential distribution. The decay rate is:

Question 7 options:

0.1666

0.6666

0.3333

0.5000

Question 8 (1 point)

Question 8 options:

The caller times at a customer service center has an exponential distribution with an average of 10 seconds. Find the probability that a randomly selected call time will be less than 25 seconds? (Round to 4 decimal places.) Answer:

Question 9 (1 point)

Suppose that the longevity of a light bulb is exponential with a mean lifetime of eight years. Seventy percent of all light bulbs last at least how long?

Question 9 options:

0.1175

0.1859

9.6318

0.3034

0.3682

Question 10 (1 point)

Question 10 options:

The waiting time for a taxi has a uniform distribution between 0 and 10 minutes. What is the probability that the waiting time for this taxi is less than 7 minutes on a given day? Answer: (Round to two decimal place.)

Question 11 (1 point)

Question 11 options:

Miles per gallon of a vehicle is a random variable with a uniform distribution from 25 to 35. The probability that a random vehicle gets between 25 and 34 miles per gallon is: Answer: (Round to one decimal place)

Question 12 (1 point)

Question 12 options:

The mail arrival time to a department has a uniform distribution over 0 to 60 minutes. What is the probability that the mail arrival time is more than 20 minutes on a given day? Answer: (Round to 2 decimal places.)

Question 13 (1 point)

Question 13 options:

The waiting time for a bus has a uniform distribution between 0 and 10 minutes. What is the probability that the waiting time for this bus is less than 5 minutes on a given day? Answer: (Round to two decimal place.)

Question 14 (1 point)

Question 14 options:

Miles per gallon of a vehicle is a random variable with a uniform distribution from 25 to 35. The probability that a random vehicle gets between 25 and 30 miles per gallon is: Answer: (Round to two decimal place)

Question 15 (1 point)

Question 15 options:

A local pizza restaurant delivery time has a uniform distribution over 0 to 60 minutes. What is the probability that the pizza delivery time is more than 30 minutes on a given day? Answer: (Round to 2 decimal place.)

Question 16 (1 point)

Question 16 options:

The MAX light rail in Portland, OR has a waiting time that is normally distributed with a mean waiting time of 5 minutes with a standard deviation of 2.9 minutes. A random sample of 40 wait times was selected, what is the probability the sample mean wait time is under 4 minutes? Round answer to 4 decimal places. Answer:

Question 17 (1 point)

Question 17 options:

The final exam grade of a statistics class has a skewed distribution with mean of 76 and standard deviation of 7.6. If a random sample of 32 students selected from this class, then what is the probability that average final exam grade of this sample is between 75 and 80? Answer: (round to 4 decimal places)

Question 18 (1 point)

Question 18 options:

The average amount of water in randomly selected 16-ounce bottles of water is 16.1 ounces with a standard deviation of 0.5 ounces. If a random sample of thirty-six 16-ounce bottles of water are selected, what is the probability that the mean of this sample is less than 15.9 ounces of water? Answer: (round to 4 decimal places)

Question 19 (1 point)

Question 19 options:

The time a student sleeps per night has a distribution with mean 6.3 hours and a standard deviation of 0.6 hours. Find the probability that average sleeping time for a randomly selected sample of 42 students is more than 6.5 hours per night. Answer: (round to 4 decimal places)

Question 20 (1 point)

Question 20 options:

The time a student sleeps per night has a distribution with mean 6.1 hours and a standard deviation of 0.6 hours. Find the probability that average sleeping time for a randomly selected sample of 36 students is more than 6 hours per night. Answer: (round to 4 decimal places)

Mathematics Homework Help

One Qualitative and Two Quantitative Variables Questions

 

I need help with a Statistics question. All explanations and answers will be used to help me learn.

Tell us about your chosen career (nursing). Identify three variables, one qualitative and two quantitative, that would be vital for your responsibilities in your chosen career. Select two quantitative variables that you believe are related in some way (think correlation).

Please answer these questions for this assignment:

  • How you would collect the data?
  • What permission(s) you need to conduct the data collection?
  • What sample size is appropriate and possible?
  • What measures of central tendency and dispersion would be appropriate?
  • What tables and graphs could be used to represent the data?
  • Why would you choose to collect these variables?
  • What relationship do you believe exists between the two quantitative variables? Why?

Mathematics Homework Help

College of St Joseph A Nationwide Survey Discussion Post

 

I’m working on a statistics discussion question and need support to help me understand better.

  1. Use google to find a problem for a hypothesis test  for one proportion such as the one below.  (It is the same one as the  introduction)  Make sure you solve your own problem this week… I need the information.

Example-  How cool is Facebook?  In a recent GenX2Z American College Student  Survey, 90% of female college students rated the social network site  Facebook as “cool.”  The other 10% rated it as “lame.”  Assume that the  survey was based on a sample of 500 students.  A marketing executive at  Facebook wants to advertise the site with the slogan “More than 85% of  female college students think Facebook is cool.”  Can he conclude that  the proportion of female college students who think Facebook is cool is  greater than 0.85?

2 .Pick another student’s problem and solve it. Make sure to include  your null and alternative hypothesis, your test statistic, your p-value,  decision, and conclusion in the context in your response. 

Another student problem : Game consoles: A poll taken by the Software Usability Research  Laboratory surveyed 341 video gamers, and 110 of them said that they  prefer playing games on a console, rather than a computer or hand-held  device. An executive at a game console manufacturing company claims that  more than 25% of gamers prefer consoles. Does the poll provide  convincing evidence that the claim is true? Use the ? = 0.01 level of  significance.

Student problem should be this : A nationwide survey of working adults indicates that only 50% of them are satisfied with their jobs. The president of a large company believes that more than 50% of employees at his company are satisfied with their jobs. To test his belief, he surveys a random sample of 100 employees, and 54 of them report that they are satisfied with their jobs. Can he conclude that more than 50% of employees at the company are satisfied with their jobs? Use the ? = 0.05 level of significance.

Mathematics Homework Help

PSYCH 655 University of Phoenix Week 3 Psychological Test Construction Discussion Question

 

I’m working on a statistics multi-part question and need an explanation to help me learn.

Hello,

In week’s one and two, we looked at the history of psychological assessment and factors that contribute to a testing being a good test (i.e., reliability, validity, ethics, etc.). In week 3, we explore what makes a test useful and use that to determine methods for test construction. Respond to the following questions in a substantive way integrating information from your text or other scholarly sources (please include citations and references for your work):

1. How would you go about making a judgment regarding the utility of a published test? What factors would you consider? What resources would you use?

2. What factors concerning test utility would you consider as you work through the process of test construction?

3. What are factors that need to be considered early in test construction to insure that the process proceeds accurately and you end up with a useful test?

4. Consider that you are constructing a test on test anxiety, what are some examples of items you would include in an assessment of an individual’s level of test anxiety? How would you determine which items should be included in the assessment? How would you evaluate the appropriateness of your items and each item’s performance in the assessment?

Mathematics Homework Help

PU Practical Application of Probability in Managerial Decision Making

 

After reading the example above where one can see how probability values can be used in managerial decision-making to establish a product guarantee, post a comment where you think probability could be used to help solve other management-type questions/problems. Think of something at work, past or present, where you could apply the techniques in the example to assist in making the best decision. If you can’t draw on life experience, then think of a product/issue where this process could be applied. Please explain your answer. Remember to cite your resources and use your own words in your explanation.

Mathematics Homework Help

BUS 308 Ashford University Week 5 Statistics for Managers Discussion

 

Step 1: Read

Step 2: Do

In a managerial report,

  • Suppose you wanted to predict Winnings ($) using only the number of poles won (Poles), the number of wins (Wins), the number of top five finishes (Top 5), or the number of top ten finishes (Top 10). Which of these four variables provides the best single predictor of winnings?
  • Develop an estimated regression equation (look at Equation 15.6 in our textbook as an example) that can be used to predict Winnings ($) given the number of poles won (Poles), the number of wins (Wins), the number of top five finishes (Top 5), and the number of top ten (Top 10) finishes. Test for individual significance, and then discuss your findings and conclusions.

Step 3: Discuss:

  • What did you find in your analysis of the data? Were there any surprising results? What recommendations would you make based on your findings? Include details from your managerial report to support your recommendations.