# GHA 2 sol - (see 1.) 8. [5] Estimate the fare for a...

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STT 200 Summer A Graded HA #2 SOLUTIONS Number of points for each problem is in brackets [ ]. The table below lists air fares from Atlanta to selected cities. 1. [5] Make a scatterplot for these data Scatterplot 0 50 100 150 200 250 300 350 400 0 500 1000 1500 2000 2500 1. [5] Find the correlation for these data Ans. 0.694 2. [5] Compute R 2 = 0.482 and explain what R 2 means in context. R 2 is the fraction of total variation of data which is attributed to the model 3. [5] Find the slope of the regression line. Ans. 0.079 Atlanta to: Distance ( x ) Fare ( y ) Baltimore 568 219 Boston 933 222 Dallas 720 249 Denver 1190 308 Detroit 602 249 Kansas City 683 141 Las Vegas 1719 252 Miami 589 229 Memphis 327 183 Minneapolis 894 209 New Orleans 419 199 NY 749 248 Okla City 749 301 Orlando 392 238 Philadelphia 657 205 St Louis 461 232 Salt Lake 1565 371 Seattle 2150 343

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4. [5] Find the y -intercept of the regression line. Ans. 177.2 5. [5] Write the equation of the linear model (regression line). Ans. x y × + = 079 . 0 2 . 177 T 7. [5] Graph the regression line on the scatterplot.
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Unformatted text preview: (see 1.) 8. [5] Estimate the fare for a 200-mile flight. Ans. 177.2 + 0.079 × 200 = 193 9. [5] Compute predicted values y ˆ and residuals 10. [5] Plot residuals Atlanta to: Distance ( x ) Fare ( y ) y ˆ Residuals Baltimore 568 219 221.87-2.87 Boston 933 222 250.57-28.57 Dallas 720 249 233.82 15.18 Denver 1190 308 270.77 37.23 Detroit 602 249 224.54 24.46 Kansas City 683 141 230.91-89.91 Las Vegas 1719 252 312.36-60.36 Miami 589 229 223.52 5.48 Memphis 327 183 202.92-19.92 Minneapolis 894 209 247.50-38.50 New Orleans 419 199 210.16-11.16 NY 749 248 236.10 11.90 Okla City 749 301 236.10 64.90 Orlando 392 238 208.03 29.97 Philadelphia 657 205 228.87-23.87 St Louis 461 232 213.46 18.54 Salt Lake 1565 371 300.25 70.75 Seattle 2150 343 346.25-3.25 Residuals-100.00-80.00-60.00-40.00-20.00 0.00 20.00 40.00 60.00 80.00 100.00 500 1000 1500 2000 2500...
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## This note was uploaded on 07/25/2008 for the course STT 200 taught by Professor Dikong during the Summer '08 term at Michigan State University.

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GHA 2 sol - (see 1.) 8. [5] Estimate the fare for a...

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