MID TERM 4points 1. For a sample of size 8, the critical values of chi-square for a 99% confidence interval for the population variance are a) b) c) d) 5,697.3572 5,629.2612 7,261.2500 6,262.2749 2 points 2. From its 32 regions, the FAA selects 6 regions and then randomly audits 25 departing commercial flights in each region requirement. This is an example of 4 a) Judgment sampling b) Cluster sampling c) Stratified random sampling d) Simple random sampling points 3. Find the probability that either event A or B occurs if the chance of A occurring is .5, the chance of B occurring is .3 and events A and B are in depend. a) b) c) d) 65 80 15 85 3points. 4. To ensure quality, customer calls for airline fare quotations are monitored at random. On a particular afternoon, ticket agent bob gives 40 fare quotations which four are incorrect. In a random sample of 8 of these customer calls. Which model best describes the number of incorrect quotations Bob will make a) Binomial b) Poisson c) Geometric d) Hypergeometric. 4 points 5. Here are statistics on order Sizes of megalith Construction supply's shipment of two kinds of constructional material last year. Mean Std. Dev. Girders 160 48 Rivets 2800 702 Which order sizes have greater variability? a) b) c) d) Cannot be determined without knowing n They are the same Rivets Girders 4 points 6. The manager of Ardmore Pharmacy knows that 25% of the customers entering the store buy prescription drugs, 65 % buy over the counter drugs and 18% buy both types of drugs. What is the probability that a randomly selected customer will buy at least one of these two types? a) .65 b) .90 c) .72 d) .85 7. Which should not be regarded as a continuous random variable? a) Length of time to play a Wimbledon tennis match b) Wind velocity at 7 o'clock this morning c) Number of personal fouls by the Miami heat in a game d) Tonnage carried by randomly chosen oil Tanker at sea. 5 points 8. A highway inspector needs an estimate of the mean weight of trucks on the interstate highway system. She selects a random sample of 49 trucks and finds a mean of 15.8 tons with a standard deviation of 3.85 tons. The 90% confident interval for the population mean a) 14.90 to 16.70 tons b) 14.69 to 16.91 tons c) 14.88 to 16.72 tons d) 14.72 to 16.88 tons 4 points 9. A large number of applicants for admission to graduate study in business are given an aptitude test. Score are normally distributed with a mean of 460 and deviation of 80. What fraction of applicants would you expect to have a score of 400 and above a) .7266 b) .07500 c) .7734 d) .2734 5 points 10. In Melanie's styling salon , the time to complete a sample is normally distributed with a mean of 25 minutes and standard deviation of 4 minutes haircut , the middle 90% of customers we require a) Between 17.2 and 32 .8 minutes b) Between 18.4 and 31.6 minutes c) Between 20 and 30 minutes d) Between 19.9 and 30.1 minutes 2points 11. Which is least likely to regarded as a ratio variable a) Number of customer complaints per day at a cable company office b) A critics rating of restaurants on 1 to 4 Scale c) Cost of an eBay purchase d) Automobile exhaust emission of nitrogen dioxide (milligrams per mile 5 points 12. Estimate the mean exam score for the 50 students in pro. Axolotl' score f 40 but less than 50 50 but less than 60 60 but less than 70 70 but less than 80 80 but less than 90 Total 6 18 14 9 3 50 a) b) c) d) 4 Points 63.5 62.0 59.2 64.01 13. Hardluck Harry has a batting average of 2(i.e. a 20 percent chance of a hit each time he bat) Scouts for rival baseball club secretly observes performance in 12 random times at bat. What is the probability that Harry will get more than 2 hits? a) .7946 b) .2362 c) .2055 d) .4417 4 points 14. TotCo is developing a new bassinet. If the length of a newborn baby is normally distributed with a mean of 50 cm and standard deviation of 5cm. Should be the interior length to ensure that 99 percent of the newborn babies will fit with safety margin of 15 cm on each of the bassinet .? a) 85.22 cm b) 95.45 cm c) 91.63 cm d) 98.92 cm 4 points 15. Last week 108 cars received parking violations in the main university lot. Of these, 27 had unpaid tickets from previous violation. Assuming that last week was a random sample of all parking violations, find 95 % confidence interval for the percentage of parking violators that have prior unpaid parking tickets. a) 16.8 to 33.2 percent b) 19.5 to 30.5 percent c) 18.1 to 31.9 percent d) 15.3 to 34.7 percent 4 points 16. On average a major earthquake (Richer scale 6.0 or above) occurs three times a decade in a certain California County. Find probability will occur next decade 5 a) b) c) d) points .1992 .1494 .9502 .7408 17. Given the contingency table show here, find the probability that either event A2 or B2 will occur. B1 A1 12 A2 26 A3 42 A4 68 Row total 148 B2 14 B3 18 Col total 44 28 44 64 150 32 47 72 169 86 133 204 467 3 points 18. Craig operates a part time plowing business using a 2002 GMC 2500 HD extended Cab short box truck. This box plot of Craig's MPG on 195 tanks of gas does support which statement? ____________________________________________________ a) b) c) d) This is very right skewed distribution The interquartile range is less than 2 MPG There are several outliers Most MPG values are concentrated in narrow range. 3 points 19. A carnival has a game of chance a fair coin is tossed. If it lands heads you win $1.00, and if lands tails you loss $0.50. How much should the ticket to play this game cost if the carnival wants to breakeven. a) 0.75 b) 0.25 c) 1.00 d) 0.50 4 points 20. Jolly Blue health care insurance JBGH is concerned about rising lab costs and would like to know what proportion of positive lab tests for prostate cancer are actually proven correct though subsequent biopsy . JBGH demands a sample large enough to ensure an error +-2 percent with 90% percent confidence. What is the necessary sample size? a) 2.401 b) 1.604 c) 4.148 d) 1.692 21. Below is sorted stem and leaf diagram for the measured speeds (miles per hour) of 49 randomly chosen vehicles on highway slowest speed in the sorted data array? Stem unit = 10 Leaf unit =1 Frequency 1 1 17 19 7 4 49 stem 4 5 6 7 8 9 a) b) c) d) 60 61 Impossible to tell 55 leaf 9 5 01222455556688999 0111233345666778999 01333557 0122 22. Below is a frequency distribution of earnings of 50 contractors in a county Earnings (thousands) Number of contractors 1-10 2 11-20 7 20-30 12 31-40 15 41-50 8 50-60 2 Regarding this distribution, which of the following is correct? a) b) c) d) 2 The class interval limits are ambiguous Too few classes were chosen The frequency distribution contains too many class intervals The class intervals are too wide. points 23. Which is the reason for using a log for time series data? a) It helps compare growth in time series of dissimilar magnitude b) General business audiences find it easier to interpret a log scale. c) On a log scale , equal distances represent equal dollar amounts d) The axis labels are usually easier to read in log units 2 points 24. \"Bob much be rich. He's a lawyer, and lawyers make lots of money \"This statement best illustrates which fallacy? a) Unconscious bias b) Confusing significance with importance c) Using poor survey methods d) Generalizing from an average to an individual 2 points 25. Smoking is not harmful. \" My Aunt Harriet smoked but lived to age 90\" This best illustrates which fallacy a) Unconscious bias b) Small sample generalization. c) Post hoc reasoning d) Significance versus practical importance. 26. Given the contingency table shown here find P(v/w). Cell phone service provider County Sprint (S) AT&T(A) Verizon (V) Row Total Macomb(m) Oakland (o) Wayne Col total 17 19 24 60 25 38 37 100 8 13 19 40 50 70 80 200 a) .5875 b) .0950 c) .4000 d) .2375 27. Find the sample Correlation for the following data x 3 7 5 9 11 13 19 21 y 8 12 13 10 17 23 39 38 a) b) c) d) .9556 .9132 .9822 .8911 4 points 28. If four items are chosen random without replacement from seven items , in how many ways can the four items be arranged treating each arrangement as a different event (i.e order is important ) a) 35 b) 840 c) 5040 d) 24 3 points 29. John scored 35 on Prof. Johnson's exam (Q1=70 and Q3 =80) Based on the fences, which is correct? a) John is unusual but not an outlier b) John is in the 30th percentile c) John is neither nor an outlier d) John is an outlier 2 points 30. Which is a time series variable a) Net earnings reported by Xena Corp for the last 10 quarters b) Visa balances of 30 students on December 31 of this year c) Dollar Exchange rates yesterday against 10 others world currencies d) Title of top 10 movies in total revenue 4Points. 31. How many ways can we choose three items at random without replacement from five items (A, B, C, and D, E) if the order of the selected items is not important? a) 60 b) 24 c) 120 d) 10 4point 32. There are 02 probabilities that a customer's Visa change will be rejected at a certain Target store because the transaction exceeds the customer's credit limit. What is the probability that the first such rejection occurs within the first 20 visa transactions. a) .4000 b) .4538 c) .1362 d) .3324