Write a questionnaire to find out the favourite cans of drink bought by the students at your school.?

State clearly the sampling frame, the sample size and how you would obtain the sample.


Describe how you could use a pilot survery.





We haven't done much about the last 2 parts of the question but my first q. is:


What is your favourite drink sold by the school?


Water/Milk/Orange Juice/Apple Juice/Ribena/Squash





Is this partly answering the question or have I got it all wrong?


Help!


Thanks...

Write a questionnaire to find out the favourite cans of drink bought by the students at your school.?
In mathematics (statistics to be precise), sampling is the random selection of a manageable group of objects (known as subset) from a very large group of objects (known as population) for observation. A sampling frame is simply the population from where you can extract your random sample. Sampling is done so because you cannot handle a large population as it costs an enormous amount of money, time and energy. After analyzing the observation obtained by studying this small group statistically, one can estimate or predict or project the observed properties to the whole population with a certain probability. In your case this population contains all the students of your school. Students you select for the forthcoming interviews is the sample or the manageable group. This sample must have a certain size for you to make the above mentioned estimation (or prediction) for the population with a certainty and, therefore, depends on the size of the population. You must ask your teacher in charge for the formulae to calculate the sample size. Oversampling (selecting more number of students than required) is a waste and undersampling (selecting less number of students than required) reduces the level of confidence of the observations (i.e. predictions are doubtful). As already mentioned the sample must be selected randomly to eliminate biasing. In other words the sample must include members from all walks of life. In your case, do not restrict the interviews to certain groups of students, instead select students who are young, old, intelligent (eggheads), bookworms, athletes, bodybuilders, tall, short, fat, thin, dieting etc. Sampling is a vital part of modern polling, market research, and manufacturing, and its proper use is vital in the functioning of modern economies.





Another technical term you should be aware of is "sample space". Informally, the sample space for a given set of events is the set of all possible values that particular events may assume. A sample space may also be known as a event space or possibility space. For example, the sample space of a toss of two coins, each of which may land heads (H) or tails (T), is the set of all possible outcomes: [HH, HT, TH, and TT]. In your case the sample space includes all the answers possible for your question(s). If you ask more than one question, then you have to list all the combinations of answers (not an easy thing to do!). For the single question you have already proposed, this sample space is [Water, Milk, Orange Juice, Apple Juice, Ribena, Squash]. If you like add the following question to your questionnaire;





What brand would you drink if you cannot get your favourite drink at the school?





For many people statistics is a boring subject. But, if you are interested in knowing more about statistics in general and sampling specifically, you can visit the following website in your leisure time. The info in these two web repositories help me a lot to formulate the answer to your question. You can also search in the Yahoo Anwers for more information





1.http://mathworld.wofram.com/


2.http://www.vrd.org/locator/sites/drmath....





Have a nice time interviewing people!
Reply:If those are the types of drink sold in cans at your school, then that's good. Does it matter if the drinks are actually in cans? If so drop off any that don't come in cans. The sample is the people you ask. Be sure to do this randomly. Don't just ask the oldest class in the school for example. Ask as many as you can (sample size) because that gives more reliable results.