Refer to the regression output below. The data set analyzed describes metal alloy that has been recovered and processed by a metal recovery firm. The recovered alloy is offered up for bid to a secondary market at approximately one week intervals although the exact day of offer varies. Each observation showed the recovery firm$$s highest bid offer per pound, the percent metal content of one shipment of the recovered alloy, and the price per pound for the aluminum alloy contract on the London Metal Exchange for the day the shipment bid offer was accepted. The variables are described below. Answer Questions $35-38$ using this information.

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Variable

Description

Price$/$lb

Highest Bid Offered for Al Alloy Shipment

Al

Aluminum percentage

Si

Silicon percentage $(\%)$

Cr

Chromium percentage $(\%)$

Ti

Titanium percentage $(\%)$

Zn

Zinc percentage $(\%)$

Pb

Lead percentage $(\%)$

LME $$/$lb

London Metal Exchange Price$/$lb on day sold

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Flag question: Question $37$

Question $376$ pts

Which number below tells us that the model is a significant predictor for $Price$/$lb of this metal alloy.

Group of answer choices

$\mathrm{.}0510$

$\mathrm{.}00000221$

$\mathrm{.}9811$

$\mathrm{.}0038$

$\mathrm{.}0022$

$\mathrm{.}0064$

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Flag question: Question $38$

Question $387$ pts

How much variation in Price$/$lb is unexplained? Round to three decimals.

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Flag question: Question $39$

Question $398$ pts

When Zn increases by $1\%,$ the Price$/$lb will $[$ Select $]["$increase$",$ "decrease"$]$ by $[$ Select $]["$$$2\mathrm{.}70","2\mathrm{.}7\%","$$$0\mathrm{.}27","0\mathrm{.}27\%"].$

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Flag question: Question $40$

Question $406$ pts

Why are Silicon and Titanium not included in the regression output?

Group of answer choices

Aluminum alloy does not contain silicon and titanium.

Their p$-$values were too close to zero.

They were considered unimportant by the analyst.

They were found to be insignificant predictors.