Solve thèse problems with STATA software

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Solve thèse problems with STATA software

1. You will find the data for this question in a file called wage.dta. The data are a sample of 300 male manual workers from the UK. We are interested in the regression of ln wage (wage) on education (educ):
lnwi =α+βedui+εi (1)
(a) Regress ln wage (wage) on education (educ). Interpret your results.
(b) Can you reject the hypothesis that an additional year of schooling increases wages by 1%?
(c) What is the R2 of the regression? Give the formula and explain what it is in words.
(d) Add years of experience (exp) to the regression. What happens to the estimated effect of educa- tion? Explain why this happens.

2. You have data from an extensive medical survey on health and economic status. A cross section of 500 men provides information on earnings w in £ per week, age in years a and an index of fitness f .
(a) You run the following regression of ln earnings on the fitness index:
ln w = 6.1 − 0.31 f + u R2 = 0.05 (2)
(3.7)
Here, and below, figures in parentheses are absolute t values and u is an error term. Calculate a
95% interval for the coefficient on the fitness index.
(b) You then add age to the regression with the following results:
lnw = 5.3+0.07a+ 0.12 f +u R^2 = 0.09 (3)
(4.8) (0.91)
Explain carefully why and how adding age to the regression can change the size and sign of the estimated fitness effect. Do the results indicate that age must be negatively or positively correlated with fitness in this sample?
(c) What economic reasons might there be to expect age and fitness to affect earnings? To what extent do you regard these results as supporting the contention that they do?

Use the professor’S corrected paper and feedback as a guideline, and revise the paper. That is, do not simply attempt to accept his corrections,make some improvement

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Use the professor’S corrected paper and feedback as a guideline, and revise the paper. That is, do not simply attempt to accept his corrections,make some improvement. NOTE: no more than. 525 words.

Assignment 2

Your employer, like many people, is concerned by the rising cost of healthcare premiums. (Note: healthcare is spelled as one word as an adjective, and as two words—health care—as a noun.) Even with the reforms enacted by Congress, premiums are ever more costly for some companies, even as more and more workers require extensive and expensive medical care.

Many workers require additional care because of illnesses and chronic conditions that are considered to be lifestyle-related, the product of smoking, drinking alcohol in excess, being overweight or obese, and the like. This added care results in added costs for your employer, who pays half of the premiums as part of an employee’s benefits package.

Your employer is considering instituting a policy requiring employees who incur extra costs because of those lifestyle-related causes to pay them. To accomplish this, he plans to charge those workers an additional 10 percent over the premiums that other workers pay.

Your employer asks you, as an economist, to justify this differential, and he wants to be able to argue from the basis of an economic principle or concept. What is that governing idea? If the differential is wrong somehow from that economic point of view, then he wants to know that, too.

Your employer will deliver his decision in a speech before stockholders and employees. You are to write the speech for him. It must be 500 words—no more than 525, no fewer than 475—to accommodate the time he has reserved for it.

As an advanced practice nurse, you will examine patients presenting with a variety of disorders.

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As an advanced practice nurse, you will examine patients presenting with a variety of disorders. You must, therefore, understand how the body normally functions so that you can identify when it is reacting to changes. Often, when changes occur in body systems, the body reacts with compensatory mechanisms. These compensatory mechanisms, such as adaptive responses, might be signs and symptoms of alterations or underlying disorders. In the clinical setting, you use these responses, along with other patient factors, to lead you to a diagnosis.
Consider the following scenario:
Scenario 1:
Jennifer is a 2-year-old female who presents with her mother. Mom is concerned because Jennifer has been running a temperature for the last 3 days. Mom says that Jennifer is usually healthy and has no significant medical history. She was in her usual state of good health until 3 days ago when she started to get fussy, would not eat her breakfast, and would not sit still for her favorite television cartoon. Since then she has had a fever off and on, anywhere between 101oF and todays high of 103.2oF. Mom has been giving her ibuprofen, but when the fever went up to 103.2oF today, she felt that she should come in for evaluation. A physical examination reveals a height and weight appropriate 2-year-old female who appears acutely unwell. Her skin is hot and dry. The tympanic membranes are slightly reddened on the periphery, but otherwise normal in appearance. The throat is erythematous with 4+ tonsils and diffuse exudates. Anterior cervical nodes are readily palpable and clearly tender to touch on the left side. The child indicates that her throat hurts a lot and it is painful to swallow. Vital signs reveal a temperature of 102.8oF, a pulse of 128 beats per minute, and a respiratory rate of 24 beats per minute.

To prepare:
� Review the three scenarios, as well as Chapter 6 in the Huether and McCance text.
� Identify the pathophysiology of the disorders presented in the scenarios, including their associated alterations. Consider the adaptive responses to the alterations.
� Review the Mind Maps Dementia, Endocarditis, and Gastro-oesophageal Reflux Disease (GERD) media in this weeks Learning Resources. Then select one of the disorders you identified from the scenarios. Use the examples in the media as a guide to construct a mind map for the disorder you selected. Consider the epidemiology, pathophysiology, risk factors, clinical presentation, and diagnosis of the disorder, as well as any adaptive responses to alterations.
To complete:
Write a 2- to 3-page paper that addresses the following:
� Explain the pathophysiology of the disorders depicted in the scenarios, including their associated alterations. Be sure to describe the patients adaptive responses to the alterations.
� Construct a mind map of your selected disorder. Include the epidemiology, pathophysiology, risk factors, clinical presentation, and diagnosis of the disorder, as well as any adaptive responses to alterations.

Include the mind in the paper at the last page maps see attached document for example of mind map

Describe and critically discuss a piece of primary research, published in a journal, and of relevance to the topics studied in the module.

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Information and instructions for the blog coursework.
Introduction

You are required to submit five blog entries, each of no more than 500 words, throughout the year. Each blog entry should describe and critically discuss a piece of primary research, published in a journal, and of relevance to the topics studied in the module. You may choose any study which you deem to be of relevance to any of the learning outcomes of the module, however your five entries should include a variety of topics and different types of study. You should assume that your audience are general medical professionals (general practitioners and pharmacists).

The aims of the exercise are to:

Increase your depth and breadth of knowledge pertaining to the module learning outcomes.
Help you to understand the research upon which therapeutics and clinical guidelines are based.
Encourage you to engage in independent study and self-directed reading which are essential for success in this module.
Encourage you to begin to develop your skills of critical analysis of research which will be extremely important to you next year when you undertake your own research projects.

Submission instructions

Each blog entry should be saved as a single Microsoft Word file (.docx) and uploaded to the appropriate repository on blackboard (below) and should include in addition to the body of the text:

A title
A reference in Harvard or Vancouver format.
A hyperlink (web link) to the article upon which you have commented
A word-count for the body of the text (ie excluding title, reference and hyperlink) which should be no more than 500 words in length.

Summative blog entries will be marked anonymously (i.e. with the marker blinded to the student’s identity) so it is important that you do not include your name anywhere in the files you submit.

Mark calculation and assessment criteria

This exercise contributes 20% towards the final module mark. The mark which will be used is the mean average of your final two blog entries. The marking criteria are broadly outlined below:

Weighting
Marking criteria 

Choice of article 10%
Was a primary research article chosen?* Was the article correctly referenced? Was a hyperlink to the article included? 

Methods 25%
Were the study methods, protocol, measurements and endpoints described appropriately? 

Results 25%
Were the results described appropriately (including quantitative description). 

Critical analysis 30%
Was relevant critical analysis included? 

Style 10%
Was the style appropriate for a blog entry and for the intended audience? Was the article written in good English. Was a word-count included* 

Total 100%
*If the blog entry does not describe a piece of primary research, exceeds the word limit, or includes an inaccurate word count, a mark of zero will be awarded

General guidance on writing blog entries

Choice of Article

You need to comment on primary research articles. If you are in any doubt as to whether an article should be considered primary research, look and see whether it has a methods section. If it does not, it is almost certainly not primary research. Laboratory studies and clinical trials make excellent choices. You could also comment on systematic reviews and meta-analyses, however, the methods used in these types of publications are quite complex (including complex statistics) and may be difficult to summarise in a short blog entry. Studies which test an explicit hypothesis perhaps lent themselves more easily to critical analysis in comparison to observational studies which look at trends in diseases or prescribing.

The inspiration for your blog entries can come from anywhere: you might read about a study in the newspaper and decide to find the original paper in an academic journal. You might come across paper during your background reading for the module. At some point, you will have to use an academic database. I will recommend the names of some below, and I would encourage you to become familiar with them and to discover which ones you find most easy-to-use. They’re very powerful search tools, and allow you to filter the results by date, or by type of article (for instance you might want to restrict your search to clinical trials only).

Pubmed

Scopus

ScienceDirect

Web of Knowledge

You may know of others, and are welcome to use them. in addition the University has its own search tool which is called ‘Discover’ and is particularly helpful, because it helps you find articles which are available in the universities electronic library collection.

The purpose of my own blog www.cardiovascularnews.co.uk is to highlight areas of interest and relevant articles to you, rather than to provide model blog entries.

Structure of your  blog entry

You can  structure your blog entry however you see fit, however you should include the following information:

Introduction

You should briefly describe the purpose and aims of the study you are describing. Remember your audience is GPs and pharmacists. You shouldn’t need to give long explanations of common medical conditions. Remember that the marks are awarded for your description and critical analysis of the research.

Description of methods

Think carefully about including the most important details in the methods, because you will not be able to include all the details. You should include details of the the experimental protocol, but do not forgot to mention what was measured (and how) and what the primary end point of the study was (or which value was compared between groups.). As your critical analysis is largely dependent on the methods, it is important to make clear how the experiment was conducted.

Description of results

It is important to discuss the most important results quantitatively and to consider the most important information to include in a short summary. Don’t be tempted to write too much about statistical significance, without commenting on the size of the effect measured. Many papers will include lots of measurements, you need to consider which are the most important, as you won’t have room to discuss them all.

Critical analysis

This is probably the most difficult section (and consequently, where the most marks are available). Essentially, you should aim to consider the work critically, rather than simply accepting the authors’ conclusion. You can approach this task by asking questions such as: Were the methods (and endpoints) appropriate? What do the results mean? Is the authors’ interpretation of the results supported by the data?

You should try to judge each paper on its own merits. If a paper set out to test the hypothesis that ‘dogs enjoy eating bones’ it’s not really fair to criticise it for not asking whether cats like eating bones. Proposing an extension to a study (however interesting) is not critical analysis. You may wish, briefly, to discuss the implications of the research which is again interesting but is not critical analysis.

Try to keep your critical analysis specific rather than general for example, rather than automatically saying ‘the experiment would have been better if the sample size had been bigger’ consider whether this is really the case. In very may experiments it is true, but it requires some justification. Experimenters don’t usually pick a sample size (n number) out of thin air, they will perform calculations to work out the sample size they need. A trial that is bigger than it needs to be costs more money and may have ethical implications relating to unnecessary experimentation on volunteers or animals. A comment along the lines of ‘the authors don’t state how they calculated their sample size’ or ‘the authors calculated their sample size but were not able to recruit enough volunteers’ is a much more useful indication that something is wrong.

It is important to comment on bias e.g. ‘there were more people with hypertension in the control group than the test group’ and to think carefully about critical analysis of the measurements and endpoints used in the trial. Many studies will claim that drug x reduces cardiovascular risk, when in fact they have only measured the effect of drug x on blood pressure, not on cardiovascular events. If a trial uses the ‘depression score’ as its endpoint, you need to question what this score is? What does it mean? Has it been validated in other trials? What are its strengths and weaknesses?. Some experiments don’t seem to have a clear hypothesis and don’t state the primary endpoint in the methods. This is often the case with trials involving mental health where the patients will be assessed for severity of symptoms using 4 or 5 different scales before and after an intervention. You should be asking if it is necessary to use so many scales , or whether the authors were ‘hedging their bets’ and hoping they would see a significant difference in at least one of the measurements.

It is also interesting to comment on the way in which numerical data are treated. For example, Some trials of antihypertensives set out arbitrary categories for BP (ie normal<140/90<hypertensive) and then presented their results saying ‘at the end of the trial 20% of people in the control group were hypertensive and 10% of people in the treatment group were hypertensive’ When data is categorised like this, it is a good idea to ask why? Is there a good reason? Or would it have been better to present the mean BP in each group? You may find it helpful to commented on the statistics used in published work. Often these are very ropy!

These are by no means the only things you can comment on, but hopefully they give some food for thought.

Avoidance of plagiarism

All blog entries will be subjected to analysis by plagiarism detection software. Students deemed to have committed plagiarism in either the formative or the summative blog entries will be initially invited to an interview with the module leader, and where appropriate, will be referred to an Academic Misconduct Panel. It is inevitable that in a short article such as this, there will be some similarity with the source paper you have used, however you nut be very careful to avoid crossing the line of what is acceptable. The University gives excellent advice on the avoidance of plagiarism which includes one definition that is very helpful: Plagiarism is..’ Verbatim copying or close paraphrasing of another’s work without clear identification and acknowledgement’ This means that whilst ‘copying and pasting’ is clearly unacceptable, so too is taking an original piece of work and altering the grammar and changing words using a thesaurus to make something ‘new’. Indeed, this may be construed as an attempt to conceal plagiarism, in which case the penalties are made mere severe.

In order to write a blog entry about a piece of research, you should know the paper ‘inside-out’ and understand it. My strong advice would be to try to write the blog entry without the paper in front of you. You will obviously need to check figures and details, but this approach should help you to avoid any allegations of academic misconduct, for which the sanctions are very serious.