In testing eight value notebook computers, PC World reported various physical and performance mea- sures of each. Data included overall rating, street price, PC WorldBench 4 performance score, and battery life,
Computer: 5 6 7 8
|
Overall Rating:
|
75
|
74
|
72
|
72
|
|
Street Price:
|
1857
|
1865
|
1699
|
1298
|
|
Performance Score:
|
100
|
98
|
104
|
91
|
|
Battery Life (hours):
|
1.88
|
3.00
|
2.38
|
2.33
|
a. From these data, obtain the multiple regression equa- tion estimating overall rating on the basis of the other three variables; then determine and interpret the approximate 95% confidence interval for the mean overall rating of notebook computers having a 1000 street price, a performance score of 100, and a 2.50-hour battery life.
b. Determine the 95% prediction interval for the overall rating of an individual notebook computer with a $1000 street price, a performance score of 100, and a 2.50-hour battery life.