Practical Business Analysis Essay

1. Re-do tot every last(predicate)y problems in habituate Problem Set 1. 2. Dollar machine Rental Co. was originally named Dollar a Day Car Rental beca economic consumption they supercharged $1.00 per day to rent a car, plus a charge per mile driven. numerous customers complained that the odometers on Dollars cars enter more miles than were actually driven. To evaluate these complaints you buzz off a random test of 6 Dollars cars, drive them on a cargonfully measured nose candy-mile course, and temperament the miles driven as registered by the odometers. The results ar 100, 105, 109, 102, 107, and 101, with the try amount deflection just about 3.578. a. development these try results, construct a 95% authorization interval for the state suppose miles recorded by all Dollar cars for a 100-mile trip. b. As a legal consultant hired by the group of the customers who complained about the odometers, do you hand enough evidence to support your clients accept? realm y our hypotheses (H0 vs. Ha), rejection region and both statistical and substantive conclusions.3. The varietys on the final interrogation given in a enlarged organic chemistry class are conventionly distributed with a mean of 72 and a standard deviation of 8. The instructor of this class wants to assign an A grade to the top 10% of the scores, a B grade to the near 10% of the scores, a C grade to the beside 10% of the scores, a D grade to the next 10% of the scores, and an F grade to all scores downstairs the 60th centile of this distribution. For each possible letter grade, examine the lowest acceptable score deep down the established range.4. The weekly demand for prevalent Motors car sales follows a normal distribution with a mean of 40,000 cars and a standard deviation of 12,000 cars.a. There is a 5% chance that GM leave behind sell more than what number of cars during the next week? b. What is the probability that GM provide sell between 20 and 23 thousand cars dur ing the next week?5. A department memory is fire in the average sense of balance that is carried on its lines quote control board. A sample of 40 accounts reveals an average balance of $1,250 and a standard deviation of $350.a. Find a 95% confidence interval for the mean account balance on this stores credit dining table. b. What sample sizing would be needed to ensure that we could augur the true mean account balance and have only 5 chances in 100 of being off by more than $100?6. A market research consultant hired by Coca-Cola is interested in determining the ratio of customers who estimation Coke over early(a) soft drinks. A random sample of 400 consumers was selected from the market under investigation and showed that 53% party favoured Coca-Cola over opposite brands.a. Compute a 95% confidence interval for the true proportion of deal who favor Coke. Do the results of this poll incite you that a majority of people favor Coke? b. Suppose 2,000 (not 400) people were polled and 53% favored Coke. Would you now be confident(p) that a majority of people favor Coke?7. BatCo (The Battery Company) produces your typical consumer battery. The party claims that their batteries last at least 100 hours, on average. Your experience with the BatCo battery has been fairly different, so you decide to conduct a test to see if the companies claim is true. You gestate that the mean look is actually less(prenominal)(prenominal) than the 100 hours BatCo claims. You decide to collect knowledge on the average battery animation (in hours) of a random sample and the teaching related to the hypothesis test is presented below. consumption this information to answer the following questions.a. You opine that the mean life-time is actually less than 100 hours, should you conduct a one-tailed or a two-tailed hypothesis test? say your alternative hypothesis. b. If you usage a 5% significance train, would you conclude that the mean life of the batteries is typica lly more than 100 hours? State the rejection region and calculate the test statistic. c. If you were to affair a 1% significance take aim in this case, would you conclude that the mean life of the batteries is typically more than 100 hours? inform your answer.8. Q-Mart is interested in comparing customer who expendd it own charge card with those who use other types of credit cards. Q-Mart would wish well to know if customers who use the Q-Mart card hap more money per see to it, on average, than customers who use some other type of credit card. They have collected information on a random sample of 38 charge customers and the entropy is presented below. On average, the somebody using a Q-Mart card spends $192.81 per visit and customers using another type of card spend $104.47 per visit. Use the information below to answer the following questions.a. Given the information above, what is pic and pic for this comparison? Also, does this represent a one-tailed or a two-tailed test? justify your answer. b. Using a 1% level of significance, is in that respect sufficient evidence for Q-Mart to conclude that customers who use the Q-Mart card charge, on average, more than those who use another charge card? Explain your answer.9. Suppose that you were asked to test H0 = 10 versus Ha 10 at the pic = 0.05 significance level and with a sample of size n = 10. Furthermore, suppose that you notice values of the sample mean and sample standard deviation and concluded that H0 be rejected. Is it true that you big businessman fail to reject H0 if you were to observe the homogeneous values of the sample mean and standard deviation from a sample with n 10? Why or wherefore not?10. Stock-market analysts are keenly interested in determining what factors influence the charge of a stock. After some examination, a statistician hypothesized that a stock value (Y in $) would be affected by its quarterly dividends (X1 in $), its price/ boodle ratio (X2), and the interest r ate of exchequer bills (X3 in %). The values of the relevant variables were observed for a period of 40 quarters. When the data were run on STATGRAPHICS PLUS, the accompanying printout was created.