PCWorld provided performance scores and ratings for 15 notebook PCs (PCWorld, February 2000). The performance score is a measure of how fast a PC can run a mix of common business applications as compared to a baseline machine. For example, a PC with a performance score of 200 is twice as fast as each notebook tested in the study, with higher scores indicating a better rating. The data are shown belowa. Construct a scatter diagram with performance score on the horizontal axis. b. Is there any relationship between performance score and overall rating? Explain. c. Compute and interpret the sample covariance. d. Compute and interpret the sample correlation coefficient. e. What does the sample correlation coefficient tell about the relationship between the performance score and the overall rating?

4. PCWorld provided performance scores and ratings for 15 notebook PCs (PCWorld, February 2000). The performance score is a measure of how fast a PC can run a mix of common business applications as compared to a baseline machine. For example, a PC with a performance score of 200 is twice as fast as each notebook tested in the study, with higher scores indicating a better rating. The data are shown below Notebook Performance score Overall rating AMS Teach Roadster 15CTA380 115 67 Compaq Armada M700 191 78 Compaq Prosignia Notebook 150 153 79 Dell Inspiron 3700 C466GT 194 80 Dell Inspiron 7500 R500VT 236 84 Dell Latitude Cpi A366XT 184 76 Enpower ENP-313Pro 184 77 Gateway Solo 9300LS 216 92 HP Pavillion Notebook PC 185 83 IBM thinkPad I Series 1480 183 78 Micro Express NP7400 189 77 Micron TransPort NX PII-400 202 78 NEC Versa SX 192 78 Sceptre Soundx 5200 141 73 Sony VAIO PCG-F340 187 77 a. Construct a scatter diagram with performance score on the horizontal axis. b. Is there any relationship between performance score and overall rating? Explain. c. Compute and interpret the sample covariance. d. Compute and interpret the sample correlation coefficient. e. What does the sample correlation coefficient tell about the relationship between the performance score and the overall rating