The fuel consortium chairman at an airport recorded the cost per barrel of crude oil and the cost per barrel of jet fuel each week.

After plotting his results, the chairman noticed that the relationship between the two variables was fairly linear, so he used the data to calculate the following least squares regression equation for predicting the cost, in dollars, per barrel of jet fuel from the cost, in dollars, per barrel of crude oil.

y^=2+7/6x

What is the residual of a week in which a barrel of crude oil costs $60 and a barrel of jet fuel costs 78$. THE ANSWER IS $6!!

The residual of the week in which a barrel of crude oil costs $60 is $6

The least square regression equation is given as:

When a barrel of crude oil costs $60, it means that x = 60.

So, we have:

Multiply

Add

So, we have:

Actual Cost = $78

Predicted Cost = $72

The residual is then calculated as:

This gives

Subtract

Hence, the residual of the week is $6

Read more about least square regression equation at:

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Residual for the week will be $6.

Step-by-step explanation:

Regression equation predicting the per barrel cost of jet fuel is,

where, = cost of jet fuel

x = cost of crude oil per week

If the cost of crude oil in any week = $60

Then predicted cost of jet fuel,

  = 2 + 70

  = $72

Residual price = Actual cost - predicted cost

                        = $78 - $72

                        = $6

Therefore, residual price will be $6.                            

answer: first option i.e. 'a' is correct.

step-by-step explanation:

since we have given that

number of minutes to wrap a small gift box = 4 minutes

we need to find the number of gifts to be wrapped in 5 minutes

since there is a direct variation, as the number of minutes will increase with   number of gifts to be wrapped.

so, let the number of gifts to be wrapped in 5 minutes be x.

so, it becomes,

hence, first option 'a'   is correct.