Statistics HW

1. Make an ungrouped frequency distribution for Price/Sales. Use the frequency distribution to find the mean, median, mode and standard deviation for Price/Sales ratio. (Note the boldface – must show and describe steps for how you USED the frequency distribution to compute the statistics) 16 pts 2. Organize the data for Profit Margin in a grouped frequency distribution using -0.20 to -0.16 as the class limits of the first class. Make a relative frequency histogram. Describe the shape of the histogram. Predict, from the shape of the histogram, whether the mean is greater than the median or vice-versa. Calculate the mean and the median. Was your prediction correct? 16 pts 3. Organize the data for Return on Equity in classes beginning with the class limits of -80 to -61. Draw an ogive for this data. Use your ogive to estimate the median. Then, find the actual median using the original data. Did the ogive provide a good estimate of the median? (Ogive is a graph of percentiles- it associates cumulative relative frequency with UPPER class boundary for each class) 16 pts 4. Determine the proportion of the data that lies within 1, 2, and 3 standard deviations of the mean for each of the variables. Determine, using the empirical rule, which of the data sets, if any, are approximately normally distributed. (16 pts) 5. Find the z-score for Kohl’s for each of the variables given. Describe, in a few sentences, the meaning of these z-scores. (16 pts) 6. Find an article that describes the results of a statistical study in which a statistic from sample was used to estimate a parameter for a population from either a newspaper, magazine, journal, or Web site. To answer this question, be sure to choose an article that mentions the sample size. I’ve recently seen many articles of this type in the New York Times (Tuesdays’ Science section is a particularly good source), Investor’s Business Daily, Health magazines, the Journal of the American Medical Association (JAMA), and the American Statistical Association Web site. I hope you will choose an article on a topic of interest to you. You should not use the same article as another student. Submit the article and a paragraph describing the population, parameter, sample, statistic, and type of data in the study described in the article. (20 pts)