Statistics Final Exam Speech or Presentation Example | Topics and Well Written Essays - 1750 words

Statistics Final Exam - Speech or Presentation Example In the case of work completed in Excel, copy and paste show the formula(s) used. No work = no credit. The problems on this exam pertain to the Malls of the Thump McDonald Property group. Thump McDonald, often referred to as â€Å"The McDonald†, commissioned his apprentices to look at various statistics to determine the efficiency of his operations. A supplier manufactures batteries for the emergency backup lights in the mall corridors. A random sample of 256 batteries is taken and the sample mean life is 6.5 years with a standard deviation of 0.65 years. The law requires 99% confidence of operation when scheduling of battery replacement. Mall security estimates that the average daily per-store theft is exactly $335, but wants to determine the accuracy of this statistic. The company researcher takes a sample of 81 clerks and finds that =$300 and s = $80. A confidence interval of 90% was used to estimate the proportion of customers who buy at least two items during their shopping mall experience. A random sample of 150 customers produced the following confidence interval: 32% +/- 4%. What is the best way to explain the results? z-test should be used when the sample size is greater than 30 (n>30) and when the mean and the standard deviation are known. T-test is best suites when the sample size is lesser than 30 (n