Block 2 Application quiz

1. Upload the files energy_usage.csv and energy_script.R to your Posit.cloud workspace.

2. Run the whole file energy_script.R

3. How long are the columns in this data set (what is n)?

• 2858

• 5

1. The RMSE of the first model is 0.514

2. The RMSE of the second model is 0.465

Which model has the better error?

• The first model

• The second model

Answer explanation

Lower error (aka RMSE) is better.

Tags

CCSS.HSS.ID.A.2

The RMSE is calculated by dividing the length(magnitude) of the residual vector by what?

• n

• sqrt(n)

• a projection

• a dot product

Tags

CCSS.8.EE.C.7B

To plot a vector, we draw an arrow starting at the origin (0,0)

• True

• False

Tags

CCSS.HSN.VM.A.1

To draw a vector, we finish the arrow at the coordinates of the vector (x,y)

• True

• False

Tags

CCSS.HSN.VM.A.1

To plot arrows in a vector field, we start an arrow at the input coordinates (x,y) and finish the arrow at the output coordinates (f(x,y), g(x,y))

• True

• False

Answer explanation

To draw a vector field, we start the arrow at the input coordinates (x,y), and we move the amount given by f(x,y), g(x,y)- left/right by f(x,y) and up/down by g(x,y)

Tags

CCSS.HSN.VM.A.1

CCSS.HSN.VM.A.2

To compute the dot product of a vector we:

• add all the entries of each vector and then multiply

• multiply the respective entries of each vector and then add them

To compute vector length(magnitude) we:

• take the square root of the vector dot product with itself

• square all the entries of the vector, add them together, and take the square root

• add the entries of the vector, square it, and then take the square root

A linear combination of vectors allows these operations:

• scalar multiplication

• vector addition

• vector subtraction

• vector multiplication

Tags

CCSS.7.EE.A.1

A matrix times a vector (assuming they are the right size to be multiplied) is always a:

• linear combination of the columns of the matrix

• solution vector

• parabola

Tags

CCSS.HSA.REI.C.8