Going extinct. A paleontologist has gathered data on fossils for a certain species of brachiopods. This species is now extinct and the scientist wants to estimate when this extinction occurred. A total of nine fossils have been discovered and dated as shown in the table below. (These data are estimated from the work of Y.G. Jin et at, “Patterns of Marine Mass Extinction,” Science,
Using each of the five methods described in the text to count tanks, compute five estimates of the date around which this species went extinct. (Use the data in the far right column of the table, then convert your answers to a date millions of years ago.) Which estimate do you think is the best? Why?
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- Urban Travel Times Population of cities and driving times are related, as shown in the accompanying table, which shows the 1960 population N, in thousands, for several cities, together with the average time T, in minutes, sent by residents driving to work. City Population N Driving time T Los Angeles 6489 16.8 Pittsburgh 1804 12.6 Washington 1808 14.3 Hutchinson 38 6.1 Nashville 347 10.8 Tallahassee 48 7.3 An analysis of these data, along with data from 17 other cities in the United States and Canada, led to a power model of average driving time as a function of population. a Construct a power model of driving time in minutes as a function of population measured in thousands b Is average driving time in Pittsburgh more or less than would be expected from its population? c If you wish to move to a smaller city to reduce your average driving time to work by 25, how much smaller should the city be?arrow_forwardThe Great White Shark. In an article titled “Great White, Deep Trouble” (National Geographic, Vol. 197(4), pp. 2–29), Peter Benchley—the author of JAWS—discussed various aspects of the Great White Shark (Carcharodon carcharias). Data on the number of pups borne in a lifetime by each of 80 Great White Shark females are provided on the WeissStats site. a. obtain and interpret the quartiles. b. determine and interpret the interquartile range. c. find and interpret the five-number summary. d. identify potential outliers, if any. e. obtain and interpret a boxplot.arrow_forward2.86 Shaft graves in ancient Greece. Refer to the American O Journal of Archaeology (Jan. 2014) study of sword shaft SHAFTS graves in ancient Greece, Exercise 2.60 (p. 61). The num- ber of sword shafts buried at each of 13 recently discovered grave sites is reproduced in the following table. 1 2 3 1 5 6 2 4 1 2 4 2 9 Source: Harrell, K. "The fallen and their swords: A new explanation for the rise of the shaft graves." American Journal of Archaeology, Vol. 118, No. 1, January 2014 (Figure 1). a. Calculate the range of the sample data. b. Calculate the variance of the sample data. c. Calculate the standard deviation of the sample data.arrow_forward
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- The article "Oxidation State and Activities of Chromium Oxides in Cao-SiO,-CrO, Slag System" (Y. Xiao, L. Holappa, and M. Reuter, Metallurgical and Materials Transactions B, 2002:595-603) presents the amount x (in mole percent) and activity coefficient y of CrO,5 for several specimens. The data, extracted from a larger table, are presented in the following table. х У 2.6 10.20 5.03 19.9 8.84 0.8 6.62 5.3 2.89 20.3 2.31 39.4 7.13 5.8 3.40 29.4 5.57 2.2 7.23 5.5 2.12 33.1 1.67 44.2 5.33 13.1 16.70 0.6 9.75 2.2 2.74 16.9 2.58 35.5 1.50 48.0 Compute the least-squares line for predicting y from x. b. Plot the residuals versus the fitted values. Compute the least-squares line for predicting y from 1/x. d. Plot the residuals versus the fitted values. C. Using the better fitting line, find a 95% confidence interval for the mean value of y when x= 5.0.arrow_forwardThe article "Estimating Population Abundance in Plant Species with Dormant Life-Stages: Fire and the Endangered Plant Grevillea caleye R Br." (T. Auld and J. Scott, Ecological Management and Restoration, 2004:125-129) presents estimates of population sizes of a certain rare shrub in areas burnt by fire. The following table presents population counts and areas (in m?) for several patches containing the plant. Агеа 3739 Population 3015 5277 1847 400 17 345 392 142 40 7000 2521 213 11958 1200 2878 707 113 1392 157 12000 10880 711 74 2259 223 81 15 33 18 1254 1320 229 351 1000 92 841 1720 1500 300 228 31 228 17 10 Compute the least-squares line for predicting population (y) from area (x). Б. a. Plot the residuals versus the fitted values. Does the model seem appropriate? Compute the least-squares line for predicting In y from In x. Plot the residuals versus the fitted values. Does the model seem appropriate? Using the more appropriate model, construct a 95% prediction interval for the…arrow_forwardThe following table shows the typical depth (rounded to the nearest foot) for nonfailed wells in geological formations in Baltimore County (The Journal of Data Science, 2009, Vol. 7, pp. 111-127). Geological Formation Group Number of Nonfailed Wells Nonfailed Well Depth Gneiss 1,515 255 Granite 26 218 Loch Raven Schist 3,290 317 Mafic 349 231 Marble 280 267 Prettyboy Schist 1,343 255 Other schists 887 267 Serpentine 36 217 Total 7,726 2,027 Let the random variable X denote the depth (rounded to the nearest foot) for nonfailed wells. Detemine the cumulative distribution function for X. Round your answers to four decimal places (e.g. 98.7654). x < 217 217arrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_ios
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