Disk drives last time Here is a scatterplot of the

Chapter 6, Problem 14E

(choose chapter or problem)

Problem 14E

Disk drives last time Here is a scatterplot of the residuals from the regression of the hard drive prices on their sizes from Exercise.

a) Are any assumptions or conditions violated? If so, which ones?

b) What would you recommend about this regression?

Exercise

Disk drives again In Chapter, Exercise1, we saw some data on hard drives. After correcting for an outlier, these data look like this: we want to predict Price from Capacity.

Capacity (in TB)	Price (in $)
0.080	29.95
0.120	35.00
0.250	49.95
0.320	69.95
1.0	99.00
2.0	205.00
4.0	449.00

Here is the regression analysis of Price vs. Capacity.

Dependent variable is Price R-squared = 98.8%, s = 17.95

Variable Coefficient

Intercept 18.617

Capacity 103.929

a) Write the regression equation. Define the variables used in your equation.

b) What does the slope mean in this context?

c) What does the y-intercept mean in this context? Is it meaningful?

d) What would you predict for the price of a 3.0 TB drive?

e) You found a 3.0 TB drive for $300. Is this a good buy? How much would you save compared to what you Expected to buy?

f) Does the model overestimate or underestimate the price for a 3.0 TB drive?

Exercise 1

Scatterplots Which of the scatterplots below show

a) little or no association?

b) a negative association?

c) a linear association?

d) a moderately strong association?

e) a very strong association?

1.

2.

3.

4.