I raised this question because of an argument I am having with a question from user697473 here. The title of his question is "Formal definiton of random assignment." In the post he makes a claim that one can get unbiased estimates of the difference of treatment effect even if one group that is represented in the population is not sampled. At least that is the way I interpret the claim. He points to a paper coauthored by Don Rubin on causal modeling here. Both he and StasK argue through examples that this claim is true. This issue was also raised in another question that he posted here. In that post titled "Random assignment: why bother?" gung expresses skeptism.
In the first question my answer included a statement to the effect that without sampling all possible assignments of a potential confounding factor you cannot construct an estimate of the difference in treatment effect without assigning samples to each stratum for the confounding factor.
I am confused about the claim. As I interpret the claim I am sure it is false. The claim is supported by two examples one given by user697473 and the other by StasK. The examples are confusing to me and in neither case is a proof or demonstration given to show that the claim is true.
I could be misinterpreting the claim but based on my interpetation it is false. To illustrate my point let's look at a famous example from the design of experiments book of the Godfather of randomization Sir Ronald Aylmer Fisher: "The Lady Tasting Tea".
In case you don't know the example I will describe it and provide a modification to clarify the example. The lady claims that she has the ability to determine just by tasting a cup of tea whether the tea was poured first or the milk was poured first. Fisher poses an experiment to test her claim by providing some cups with tea poured first and others with the milk poured first. If the Lady has the expertise that she claims she should be able to correctly identify the types better than a person who guesses at random. So the experiment is design to see if her probability of correct classification is better than 0.5. So he randomly provides the Lady with cups from both groups (in the example there were 6 cups 3 with milk poured first and 3 with tea poured first.
Now let me modify the experiment slightly. Suppose I have three brands of tea and for my population these brands are served at a tea parties equally. The question I want to ask is when given a cup of tea at a tea party can the Lady predict whether milk was poured first or the tea was poured first. I want to test whether her prediction accuracy is greater than 0.5 in the setting of tea parties. So I will apply Fisher's experiment to estimate this probability when the Lady is at one of these tea parties.
Note: I do not care whether or not she can differentiate the brands.
Suppose that in the population of tea parties the Lady's ability is:
Brand A Can predict tea first with probability 0.7 and can predict milk first with probability 0.7.
Brand B Can predict tea first with probability 0.75 and can predict milk first with probability 0.75.
Brand C Can predict tea first with probability 0.5 and can predict milk first with probability 0.6.
So she does no better than chance with Brand C but can do better than chance with Brands A and B.
For the experiment I only provide Brands A and B for her to taste. All I want to know is her ability to predict correctly in the normal tea party situation.
Can I get an unbiased estimates of her prediction capabilities with this experiment?
If the answer to (1) is no, is user697473's claim false or have I misinterpreted it?
Randomization is used to avoid bias that is produced by confounding variables. This is important when trying to draw inference from a sample to a population. In my example the Brands are confounders. The treatment is tasting the cups. In the population she would get Brand A, Brand B and Brand C each 1/3rd of the time. If I know this and I sample Brands with unequal probabilities I claim that I can get an unbiased estimate of her prediction capabilities by taking a specific weighted average of the estimates of the proportions if I use a stratified random sample with strata totals n1, n2 and n3all greater than 0. But I cannot if n3 = 0. Furthermore, there is not other estimate I can calculate from a sample where allocation to Brand C equal 0 that will be an unbiased estimate.
I choose to apply for the English Teaching department in your esteemed university not only for my great interest and burning enthusiasm in this field, but also because I am really determined to be involved in the related study and work in the coming future. I have decided that I will contribute all of my life in English Teaching. My career goal is to become an outstanding English teacher stepping into the new period in order to apply the more scientific teaching methods and ways into practice. That is just where my interest lies.
Meanwhile, I must acknowledge that my choice of TESOL never comes from my hot mind, but from the continuous learning and practices. So, it is actually a determination rather than a mere choice. Taking advantage of my excellent score in English learning, I have been involved in the social work as family teacher as well as attending some professional trainingto broaden my horizon since my freshman year. Theformer experiences enabled me to find that it is really exciting to be devoted to English Teaching field and such kind of excitation used to roll up in me every time, which made me believe that it is just the enterprise that I will be devoted to with my whole life.
Cherishing this determination, I began to make insistent efforts to achieve my dream by participating more teaching activities to accumulate the related experiences. It still occurs to me that once in an activity, I met with a student with very poor foundation in English. However, during my contact with him, I found that he was actually gifted in language learning and his English is poor just because he dislikes the boring “signals” without any “nutrition”. Taking his interest into full account, I brought out one of my speeches before and he turned out to be deeply attracted by the words of “Wine is soaking, memories are passing. Wound is recovering, just for never forgetting.” He told me that it is the first time for him to realize that English can also express the sorrows so incisively and vividly. In this way, I successful lightened his interest in English, according to which I designed a special teaching scheme for him with the Tagore poems instead of traditional texts or grammar. Besides, I even advised him to read the English edition of “The Book of Songs” to cultivate his interest and feelings to the new language. Meanwhile, I also found some original edition of “English and American Literature”, telling him to translate them into his interested literary form. Benefiting from my special teaching scheme on him, his interest in English was being heated, which witnessed his great improvement in English reading ability. This successful experience presented me with much more confidence for my future work.
The following teaching experiences after that enabled me to realize that few people are learning English as a kind of language, but as a kind of science like mathematics. So the sentence patterns are just like the mathematical formulas that are tormenting their memories since they can only put all the sentences into “frameworks”. In this way, they will easily get puzzled once the expression is changed because they are fettered in the grammar or the stupid “sentence patterns” with little understanding on the flexibility of a language. Thus, during my teaching, I have been trying to tell all of my students that grammar is just a way to help us to express our ideas in a scientific and acceptable way and they can actually write any thing in their own manner instead of thinking too much of the grammar requirements. However, I realized that my teaching way is not enough to pull up the root of the problem though I actually help a few of the students indeed because under Chinese boring education, English can be only considered as a subject instead of a language, which is just the problem existing in Chinese education system.
Therefore, I hope to find a more suitable English teaching methodfor Chinese students, which can pull them out of the fixed clues by telling them that language is not just a tool, but also anexpression and communication that carries full emotions of human beings. Generally, I have every reason to believe that cherishing this kind of attitude and enthusiasm, I must be able to make more achievements after the study in your gorgeous learning institute, which will largely improve my personal professional quality and abilities and promote me to achieve my career goal in the coming future.
MIT Sloan MBA Essay Example
The following MBA admission essay was submitted to the Wharton business school by Aringo's client. The client was admitted to the program. Several names and details in this essay sample were changed to protect client privacy.
The application essay question / topic:
Question: Please describe a time when you coached, trained, or mentored a person or group.
I had been Bar Manger in the Green Villa for two years, where I was managing bar responsibilities in events of up to 400 people, when I decided to leave in order to manage my grandfather's business. I had been in charge of recruiting, training and managing the over 10 bartending employees as well as pricing and managing $10,000 worth of inventory.
When I handed my resignation to the manager, I assured him that I would not only find my replacement, but properly train him/her no matter how long it took.
Emotionally attached to the place and the people, I was very passionate about the bar and its development. I considered it my personal mission to find someone who would be the best for the job. I began by reviewing my 5-person staff to determine if anyone 'in-house' was qualified to take over; otherwise, I would have had to explore the option of hiring someone. I much preferred promoting from within, despite the lack in management experience. I believed the high level of commitment of my employees, as well as their excellent relationships with the rest of the Green Villa staff, was crucial.
I knew that I had a rough diamond among my staff, Dan. Extremely efficient and professional, Dan possessed excellent customer relations skills and got along well with his fellow employees. In spite of all these elements there was a big problem – his maturity. I knew I had a huge task ahead of me: guiding Dan through the transition from an employee mind-set of a manager. I knew that given the right guidance, Dan was the best candidate to replace me. I was eager to help him become the professional manager that the Green Villa deserved.
I related my decision to the company manager and he agreed that Dan was the right person for the job. When I offered Dan the position, he was very delighted and accepted on the spot.
I began by taking him through the logistic responsibilities. To ensure that Dan approached each task with the necessary attention, I stressed the importance of each responsibility for ensuring Customer satisfaction. Within 2 weeks I encouraged Dan to assume logistic responsibilities while I monitored. Believing dialog is a crucial tool for guidance, when the occasional mistake occurred I would point it out and discuss with him the logic behind the appropriate decision-making process. I saw that Dan responded well to this kind of feedback, as his organizational capabilities strengthened and his confidence grew.
The most delicate aspect of this training period was managing the transition of Dan's status in relation to the staff. This was crucial to both shift assignments and actual work behind the bar. I stressed to Dan the considerations that must guide him when filling all shifts: as the manager, he is responsible for ensuring a balance between creating a strong team and considering employees' availability, abilities and needs.
I emphasized the importance of personal example, responsibility and welcoming feedback from the staff. Through an exercise where we conceptualized the ideal employee, we highlighted traits Dan must aspire to demonstrate through his work as manager.
After 2 months, I knew Dan was ready. I gave him control over all responsibilities, under my supervision. Of the opinion that mistakes are an indispensible part of learning, I would only intervene on rare occasions. I would offer my feedback after events and we would review what had happened. I first challenged him to analyze the event through his eyes. Then I suggested alternatives and pointed out several things he had missed, discussing the implications both on the event and the long-term work.
After 3 months, the time came for my final goodbye. I made it clear to Dan that I would always be available. I knew the bar was in good hands: Dan had effectively transformed from team-mate to professional manager. He earned the trust of his employees, providing constructive criticism and positive feedback when needed, while being attentive to their needs. A month later, when I stopped by, the HR told me that I had made the right choice, and that Dan was proving himself to be quite an effective manager, confident and full of initiative. When Dan called me 2 months later, thanking me for pushing him forward and guiding him, I felt great personal satisfaction.
Why would you like to attend Brandeis? (250)
It's like the wonderland of mine, I am not Alice, and the wonderland is not the underground world. However, life is always the fantastic adventures which filled with surprises and chances, and I am sure that Brandeis University would be the wonderland of mine which could help me to experience more and improve myself to be a better person.
I want to be a person who can help other people and contribute to the society, then I should have enough capabilities first and Brandeis attracts me. I'd like to study psychology and Brandeis offers students best education, researches opportunities and full support.
In Brandeis, psychology majors study varied aspects of both basic and applied areas of the field and focus on basic scientific research for undergraduate involvement. Brandeis offers a wide range of opportunities to participate in research, and I am looking forward to join in the researches with excellent professors there to write papers for publication in professional journals and books. What's more, there are undergraduate departmental representatives (UDR) there who can help every student individually to students' problems and suggestions to the faculty.
There would be thousands of words to describe my passion for the Brandeis students' life, organizations, clubs, athletics, community involvements, etc. However, there is also another reason why I eager to live in Brandeis besides of those outstanding academic advantages and campus diversities, I have a friend who joined in the college fair and shared with me her impressions for the school officer, harmonious, friendship, charming and attractive, I also wish to meet the wonderful friends there.
essay在开头部分写道：生活是一场冒险总是充满惊奇和机会，一句话概括了作者对生活的理解，同时也反映了作者热爱生活的一面。接着把布兰迪斯比作爱丽丝历险记的 wonderland, 太有创意了。
assignment在我们以前学习英语的时候，只知道它是作业的意思。而随着我们的长大，甚至出国留了学，却发现我们不会写assignment了，为 什么？在欧美，一些大学的assignment其实有两种，一种是报告形式，另一种则是文章、短文的形式。它们需要各专业的专业性知识，用这两种形式来完 成导师布置的相关任务。那么从国内去海外留学的留学生们怎么去适应欧美的这些assignment呢？本站可为您提供专业的指导服务，接下来先让我们来参 详一下某海外assignment要求，供大家参考。
Written Assignment and Guidelines for Submission
Discuss the effects of ageing under each of the following headings:
A hard copy of the 1000 to 1250 word assignment is due no later than 17:00 hours on Friday 15th April (end of week 7).
Late submissions will not be accepted unless an Assignment Extension has been granted by the Course Coordinator Dr Tony Bush.
Extension forms are available from the School of Health Sciences office on Level 4 of Building 201 (for Bundoora students) or from the School website on the RMIT internet. Students must follow School policy when applying for an extension; and must not assume that it will be granted automatically.
Guidelines for submission
These guidelines are intended to assist students in formulating a comprehensive and appropriate response to the question. The purpose of this assignment is for students to gain an understanding of the biological, behavioural and psychosocial changes that occur with ageing. Throughout this process students can apply knowledge gained though lecture material.
Students must use these guidelines to format their assignment. This requires the student to write a brief introduction which should include introducing the topic, and stating what their intentions are in their response to the question.
A conclusion is also required, in which the student is required to summarise the major points covered in their submission.
The use of headings is mandatory to provide clearly structured signposts for both the student and the examiner. Adherence to the marking guide will ensure that students present their submission in a professional and academic style.
Students are not to submit additional information as an Appendix. Headings related to specific content should be used to organise your information, and table of contents must be included.
An overall word limit of 1000-1250 words is required for this assessment. Students are not to go over the word limit by more than 250 words. If students are under the minimum word limit, it may mean that they have not answered the question in enough detail.
References & Referencing:
Students are to show evidence of research into the topic; in addition to the required textbook for this course. A minimum number of three (3) references used must be relevant to the topics, and must be contemporary (not older than 5 years generally) and relevant to the context of Ageing. The types of references used should include the textbook & journal articles (minimum of 2).Students should research the topic through the RMIT Library databases and e-journals.
Students must reference all information from other sources, using appropriate intext referencing according to the American Psychological Association (APA) style of referencing. This includes intext referencing, and page numbers for direct and indirect quotes. Students must also include a reference list at the end of their assignment written exercise, formatted according to APA referencing style. Students can access information on formatting according to APA through the RMIT Library webpage (under the subject guide – Nursing –referencing – APA), on the Study and Learning Centre webpage or the Style Guide: Strategies for Effective Academic Writing on the DLS. . Students are advised to maintain an ongoing list of all references used during the writing of assignment; including details of web addresses, dates that sites were accessed, page numbers, etc.; to help them collate their final list.
Spelling, Grammar & Presentation:
Students must ensure that their spelling and grammar, including punctuation, meets academic standards. Spell checks on the computer are useful; but students need to also do a final read-through of their submission to check for errors. It is expected that students will also use professional language and terminology. This should include using and defining medical terms, in keeping with the expectations of registered nurses within the health care setting. The use of abbreviations should be limited to those commonly used, and should be written in full the first time used in the submission. Students are not to use their own shorthand or SMS type. The font used should be a clear typeface, and size 12. Normal size margins apply and double spacing, with students ensuring pages are numbered clearly.
Students are to submit only a hard copy of their Assignment by or on the due date, following the instructions on the course DLS. Electronic submission may be asked for, when incidence of plagiarism is suspected so the assignment can be put through Turnitin©. Assignments are not to be emailed to the Course Coordinator. Students are also reminded to retain a hard and/or electronic copy of their submission; until after the final course marks have been collated, finalised and released to students.
The assignment will be available for collection from the course coordinator after the official release of results.