Retail Price Data for N = 60 Hard Disk Drives $y =$

question 25

Essay

Retail price data for n = 60 hard disk drives were recently reported in a computer magazine. Three variables were recorded for each hard disk drive: $y =$ Retail PRICE (measured in dollars)
$x _ { 1 } =$ Microprocessor SPEED (measured in megahertz)
(Values in sample range from 10 to 40 )
$x _ { 2 } =$ CHIP size (measured in computer processing units)
(Values in sample range from 286 to 486 )

A first-order regression model was fit to the data. Part of the printout follows:

$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\text { Analysis of Variance }$
$\begin{array}{lrrrrr}\text { SOURCE } & \text { DF } & \text { SS } & \text { FS VALUE } & \text { PROB }>\text { F }\\\text { MODEL } & 2 & 34593103.008 & 17296051.504 & 19.018 & 0.0001 \\\text { ERROR } & 57 & 51840202.926 & 909477.24431 & & \\\text { C TOTAL } & 59 & 86432305.933 & &\end{array}$

$\begin{array}{llll}\text { ROOT MSE } & 953.66516 & \text { R-SQUARE } & 0.4002 \\\text { DEP MEAN } & 3197.96667 & \text { ADJ R-SQ } & 0.3792 \\\text { C.V. } & 29.82099 & &\\\hline\end{array}$

Test to determine if the model is adequate for predicting the price of a computer. Use $\alpha = .01$ .

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Definitions:

Series Motor

A motor that contains only a series field winding.

No Load

A condition where a power source or device is operating without any load or consumption, indicating its behavior in an ideal or unloaded state.

Square Wave Voltage

A waveform of voltage that switches between high and low states, creating a square shape.

DC Average

The average value of a direct current (DC) signal over a period of time, usually calculated by integrating the signal over that period and dividing by the period's length.