Answer the following questions and read instructions carefully.
Problem #1 The previous month's rainfall in millimeters was recorded at the same time of year in a certain geographical region: 289, 298, 306, 306, 306, 315, 324, 341, 348, 358, 358, 375, 427, 445, 702 Answer the following: a) Give the 5-number summary and draw a box plot. Do this manually (that is, do not use R). Free hint: Remember that after calculating the median, that number is now "used" and therefore is not included when proceeding to figure out Q1 and Q3. That is, once you have "used" a data point, it is no longer used for any remaining calculations (eg. Q1 or Q3). This also applies if you use 2 data points and take the mean between them. To get your boxplot into your homework document, keep it simple. For example, you do not have track down a scanner! Feel free to do something simple like taking a photo with your phone and paste it from there. Using R, create do the following: b) Create a vector of the above values. Paste the code you used to create this vector into your answer document. c) Calculate the mean and median using R. Paste the result from R into your answer document. d) Using R, determine the 5-number summary. Paste the code you used to do this into your answer document. And of course, also paste the actual 5-number summary that R gives you into your answer document. Note: R may give a slightly different 5-number summary than your manual calculation. This is okay, different statistical software programs can sometimes do these calculations differently. We will discuss this topic in a little more detail down the road. e) Compare the mean and median values of this variable. Of the various centers of a distribution discussed in this week’s lectures, which statistic do you think is the best choice to represent the center in this particular set of values? (If you don’t understand the question, then be sure to go back and review the lectures!) Explain your reasoning. Problem #2 Track down a chart that you believe is misleading in some way. You certainly should not spend hours looking. Simply try to find something that you feel is vague or misleading in some way and explain why you think that is. Be sure to copy/paste the chart into your document so that the grader can see what you are referring to. Please do not paste URL hyperlinks since these may not be available by the time the grader sees it or may be behind a paywall. Problem #3 Explain why it is important to subscribe to News postings. (Hint: You will receive an email about this during your first week.) Also write a short statement indicating that you are aware of the importance of news postings in an online course, and that you promise to read all news postings carefully. Sign this statement by typing your name at the end of your statement. Summarize in your own words the #1 tip of the course mentioned in the 'Welcome to the course' email that was sent out at the beginning of the quarter. Do a quick google search on this topic and provide the link to one article you find on the subject. The Checklist 1. Submit as Google or Word Document: Your submissions should always be in DOCX (Word) or Google Doc format. Do not submit as PDF. 2. Always show your work: As mentioned in the past, I don't expect you to go into painful detail of every step, but the grader must have a decent idea of how you arrived at your answer. 3. Describing a distribution: When asked to describe a distribution, this should include at least one chart (typically a histogram or a boxplot -- and including both is okay), and descriptive statistics (center, spread, 5-number summary). 4. All graphs should be included in your document. 5. Include title and labels on graphs: When drawing a graph, you should always include a title, and at the label on at least one axis (histograms and boxplots), and for some graphs, such as scatterplots, you should have labels on both the x and y axes. 6. Create vectors in R: When you are provided with a series of values and expected to do things with them using R, you will almost certainly want to place those values inside an R vector. 7. Always include your R code in your assignments: In addition to providing numeric solutions from your R output, you should, of course, also include any R code you wrote to generate that output. 8. Be prepared for questions that can not be answered: I will be throwing these at you from time to time. I promise that my goal here is not to trick you! However, you must be aware that in the real world, people will often come up with statistical and mathematical conclusions where they are not appropriate. You will come to see that I am far more interested in pushing all of you to ensure that you grasp concepts, than I am in making you spend hours crunching numbers. Types of questions that can not be answered: 9. Not enough information: As a very simple example, if I gave you a mean but did not give you an standard deviation, then you would not be able to answer the question because you have not been given enough information. 10. Inappropriate for the type of calculation being asked: If, for example, you are asked to do normal distribution calculations, but you plot the data (and you should always plot the data!) and it turns out to be skewed, then doing calculations that require a normal distribution is inappropriate and would lead to faulty conclusions. Another example would be if you were asked to generate a linear regression model - but you plot the data and see the relationship is not linear! 11. In cases like the above, all you have to do is to indicate as much your answer and you will receive full credit for that problem!