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1 Stuent: Dte: Instructor: Doug Ensle Course: MAT117 1 Applie Sttistics - Ensle Assignment: Online 6 - Section of 7 9/14/15, 1:27 AM

2 1. 2 of 7 9/14/15, 1:27 AM

3 The t on the right shows the percent of the popultion in countr tht uses cell phones n their GDP, in hunres of billions of ollrs. Let = cell-phone use n = GDP. Complete prts through e below.. The grph on the right shows sctterplot. Describe this plot in terms of the vribilit of cell-phone use vlues for ntions with low GDP. A. There is gret vribilit of cell-phone use. Cell-phone use is not close to. B. There is little vribilit of cell-phone use. Cell-phone use is lso close to. C. No conclusions cn be rwn. Full t set Countr A B C D E F GDP Cellulr Countr G H I J K L GDP Cellulr Cellulr % b. Give the - n -coorintes for the ntion tht hs the highest cell-phone use. (Tpe n orere pir.) c. Use softwre to clculte the correltion coefficient between the two vribles. r = (Roun to three eciml plces s neee.) Wht is the sign of the coefficient? Eplin wht the sign mens in the contet of the problem. Choose the correct nswer below. A. The sign is negtive, mening tht s the GDP increses, the percentge of cell-phone use ecreses. B. The sign is positive, mening tht s the GDP increses, the percentge of cell-phone use increses. C. The correltion is close to, mening tht there is no correltion in the grph.. Ientif the ntion tht hs the lest cell-phone use s compre to wht ou woul epect, given their GDP. Countr Ientif the ntion tht hs the most cell-phone use s compre to wht ou woul epect, given their GDP. Countr e. If the correltion coefficient ws reclculte fter removing the two observtions ientifie in prt, how woul the resulting coefficient compre to the one obtine in prt c? GDP (in 1 billions) 4. A. The resulting coefficient woul be closer to positive or negtive 1. B. The resulting coefficient woul be closer to. 3 of 7 C. There woul be no chnge in the 9/14/15, 1:27 AM correltion.

4 ID: T 2. For tble of ntionl informtion it is foun tht the correltion with Internet use is.767 for GDP,.692 for cellulr-phone use,.882 for literc,.565 for fertilit, n.55 for CO 2 emissions. Use this informtion to nswer prts through c.. Which vrible hs the strongest liner ssocition with Internet use? A. CO2 emissions hs the strongest liner ssocition with Internet use. B. Fertilit hs the strongest liner ssocition with Internet use. C. Cellulr-phone use hs the strongest liner ssocition with Internet use. D. Literc hs the strongest liner ssocition with Internet use. E. GDP hs the strongest liner ssocition with Internet use. b. Which vrible hs the wekest liner ssocition with Internet use? A. Literc hs the wekest liner ssocition with Internet use. B. Fertilit hs the wekest liner ssocition with Internet use. C. GDP hs the wekest liner ssocition with Internet use. D. Cellulr-phone use hs the wekest liner ssocition with Internet use. E. CO2 emissions hs the wekest liner ssocition with Internet use. c. Suppose the correltion between totl number of Internet users n cell-phone users iffers from tht of Internet use n cell-phone use. Eplin wh this ifference might eist. Choose the correct nswer below. A. Some Internet users m use the Internet more or less thn others. Likewise, some cell-phone users m use their cell-phones more or less thn others. B. The totl number of Internet users is ifferent thn the totl number of cell-phone users. C. The Internet is use more thn cell-phones. D. Most Internet users use the Internet the sme mount s others. Likewise, most cell-phone users use their cell-phones the sme mount s others. ID: of 7 9/14/15, 1:27 AM

5 3. Mtch the sctterplots to the right with the correltion vlues. 1. r = 2. r = 1 3. r = 1 4. r =.4 () 1. Sctterplot (1) 2. Sctterplot (2) (b) 3. Sctterplot (3) 4. Sctterplot (4) (c) () (1) b (2) c (3) c (4) b c c b b ID: of 7 9/14/15, 1:27 AM

6 4. Use the t set to the right to nswer the following questions Sketch sctterplot. A. B. C. D b. If one pir of (,) vlues is remove, the correltion for the remining four pirs equls 1. Which pir is it? (Tpe n orere pir.) c. If one vlue is chnge, the correltion for the five pirs equls 1. Ientif the vlue n how it must be chnge for this to hppen. The vlue of (1) woul hve to chnge to. (1) ID: of 7 9/14/15, 1:27 AM

7 1. B. There is little vribilit of cell-phone use. Cell-phone use is lso close to. (28.8,96.7).862 B. The sign is positive, mening tht s the GDP increses, the percentge of cell-phone use increses. G J A. The resulting coefficient woul be closer to positive or negtive D. Literc hs the strongest liner ssocition with Internet use. E. CO2 emissions hs the wekest liner ssocition with Internet use. A. Some Internet users m use the Internet more or less thn others. Likewise, some cell-phone users m use their cell-phones more or less thn others. 3. (1) b (2) c (3) (4) 4. C. 1 (7,5) (1) of 7 9/14/15, 1:27 AM