Instructions

need .R or RStudio needed for this. found at their website here:

Class Exercise.R (file://DESKTOP-1E8F4IA/Users/nafig/Downloads/Class%20Exercise.R)

The dataset in the website below:

https://docs.google.com/spreadsheets/d/14MNXymkzpu2axMq9k9TyHXCIeJI1QN4_n6t9ZdK025I/edit?usp=sharing

First go through the Class Exercise.docx document and accompanying R script file and carefully follow each step in the document and write down your answers. When you have finished, transfer your answers below.

Question at position 1

1

1 point

Question 1 is unpinned. Click to pin.

Question at position 1

Do the variables seem normally distributed?

Do the variables seem normally distributed?

Yes

No

Question at position 2

2

1 point

Question 2 is unpinned.

Question at position 2

Which of the below issues do you see

Which of the below issues do you see with the data (if any)?

Heteroscedasticity

Multicollinearity

Non-linearity

Non-independence of observations

Question at position 3

3

1 point

Question 3 is unpinned. Click to pin.

Question at position 3

For any identified in the two responses above, how would you correct them? (try some different transformations and see what seems to work best).

For any identified in the two responses above, how would you correct them? (try some different transformations and see what seems to work best).

Squaring or cubing salary

Squaring or cubing years

-1/salary

-1/years

sqrt(salary)

sqrt(years)

log(salary)

log(years)

Question at position 4

4

1 point

Question 4 is unpinned. Click to pin.

Question at position 4

In Model 1, is the IV significant?

In Model 1, is the IV significant?

Yes

No

Question at position 5

5

1 point

Question 5 is unpinned. Click to pin.

Question at position 5

In reporting the results of Model 1, how much of the variance of salary would we say was accounted for by the model (report as a percentage rounded to 1 decimal place)? Question Blank 1 of 1%

Question at position 6

6

1 point

Question 6 is unpinned. Click to pin.

Question at position 6

What do you notice after looking at the scatterplot plus the regression line and confidence intervals? Does it look like the model performs equally well across all values of the IV?

Display keyboard shortcuts for Rich Content Editor

What do you notice after looking at the scatterplot plus the regression line and confidence intervals? Does it look like the model performs equally well across all values of the IV?

12pt

Paragraph

Question at position 7

7

1 point

Question 7 is unpinned. Click to pin.

Question at position 7

Do you notice anything amiss looking at the plot of the residuals vs the predicted values?

Display keyboard shortcuts for Rich Content Editor

Do you notice anything amiss looking at the plot of the residuals vs the predicted value

12pt

What does your model predict regarding the average salary of all employees with 15 years of experience at the 95% confidence level?

What does your model predict regarding the average salary of all employees with 15 years of experience at the 95% confidence level?

95% confident it's between $129,207.40 and $140,495.10

It's exactly $134851.30

95% confident it's between $80,273.37 and $189,429.20

Question at position 9

9

1 point

Question 9 is unpinned. Click to pin.

Question at position 9

What does your model predict regarding the salary of a single employee with 6 years of experience at the 95% confidence level?

What does your model predict regarding the salary of a single employee with 6 years of experience at the 95% confidence level?

95% confident it's between $49,461.75 and $164,781.75

It's exactly $57,121.75

95% confident it's between $2,298.69 and $111,944.80

Question at position 10

10

1 point

Question 10 is unpinned. Click to pin.

Question at position 10

Now run the regression of log(salary) by years. Is the IV significant?

Now run the regression of log(salary) by years. Is the IV significant?

Yes

No

Question at position 11

11

1 point

Question 11 is unpinned. Click to pin.

Question at position 11

In reporting the results of Model 1, how much of the variance of salary would we say was accounted for by the model (report as a percentage rounded to 1 decimal place)? Question Blank 1 of 1%

What do you notice after looking at the scatterplot plus the regression line and confidence intervals? Does it look like the model performs equally well across all values of the IV?

Display keyboard shortcuts for Rich Content Editor

What do you notice after looking at the scatterplot plus the regression line and confidence intervals? Does it look like the model performs equally well across all values of the IV?

12pt

Paragraph

Question at position 13

13

1 point

Question 13 is unpinned. Click to pin.

Question at position 13

Do you notice anything amiss looking at the plot of the residuals vs the predicted values?

What does your model predict regarding the average salary of all employees with 10 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

What does your model predict regarding the average salary of all employees with 10 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

We're 95% confident it's between $75,390 and $82,024

It's exactly $78,637

We're 95% confident it's between $53,233 and $116,165

Question at position 15

15

1 point

Question 15 is unpinned. Click to pin.

Question at position 15

What does your model predict regarding the salary of a single employee with 12 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

What does your model predict regarding the salary of a single employee with 12 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

We're confident it's between $88,538 and $95,754

It's exactly $92,075

We're confident $62,350 and $135,973

Question at position 16

16

1 point

Question 16 is unpinned. Click to pin.

Question at position 16

Now run the regression of log(salary) by sqrt(years). Is the IV significant?

Now run the regression of log(salary) by sqrt(years). Is the IV significant?

Yes

No

Question at position 17

17

1 point

Question 17 is unpinned. Click to pin.

Question at position 17

In reporting the results of Model 1, how much of the variance of salary would we say was accounted for by the model (report as a percentage rounded to 1 decimal place)? Question Blank 1 of 1%

What do you notice after looking at the scatterplot plus the regression line and confidence intervals? Does it look like the model performs equally well across all values of the IV?

Display keyboard shortcuts for Rich Content Editor

What do you notice after looking at the scatterplot plus the regression line and confidence intervals? Does it look like the model performs equally well across all values of the IV?

12pt

Paragraph

Question at position 19

19

1 point

Question 19 is unpinned. Click to pin.

Question at position 19

Do you notice anything amiss looking at the plot of the residuals vs the predicted values?

What does your model predict regarding the average salary of all employees with 5 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

What does your model predict regarding the average salary of all employees with 5 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

We're 95% confident that it is between $51,176 and $58,035

It's exactly $54,498

We're 95% confident that it is between $35,535 and $83,580

Question at position 21

21

1 point

Question 21 is unpinned. Click to pin.

Question at position 21

What does your model predict regarding the salary of a single employee with 21 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

What does your model predict regarding the salary of a single employee with 21 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

We're 95% confident it's between $166,678 and $188,438

It's exactly $177,225

We're 95% confident that it's between $115,584 and $271,738

Question at position 22

22

1 point

Question 22 is unpinned. Click to pin.

Question at position 22

Now run the regression of salary by sqrt(years). Is the IV significant?

Now run the regression of salary by sqrt(years). Is the IV significant?

Yes

No

Question at position 23

23

1 point

Question 23 is unpinned. Click to pin.

Question at position 23

In reporting the results of Model 1, how much of the variance of salary would we say was accounted for by the model (report as a percentage rounded to 1 decimal place)? Question Blank 1 of 1%

What do you notice after looking at the scatterplot plus the regression line and confidence intervals? Does it look like the model performs equally well across all values of the IV?

Display keyboard shortcuts for Rich Content Editor

What do you notice after looking at the scatterplot plus the regression line and confidence intervals? Does it look like the model performs equally well across all values of the IV?

12pt

Paragraph

Question at position 25

25

1 point

Question 25 is unpinned. Click to pin.

Question at position 25

Do you notice anything amiss looking at the plot of the residuals vs the predicted values?

Display keyboard shortcuts for Rich Content Editor

What does your model predict regarding the average salary of all employees with 19 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

What does your model predict regarding the average salary of all employees with 19 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

We're 95% confident that it's between $157,927 and $175,108

It's exactly $166,518

We're 95% confident that it's between $100,357 and $232,678

Question at position 27

27

1 point

Question 27 is unpinned. Click to pin.

Question at position 27

What does your model predict regarding the average salary of all employees with 4 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

What does your model predict regarding the average salary of all employees with 4 years of experience at the 95% confidence level? (note: order of operations and rounding could lead to slight variations in your answers. Pick the answer below that most closely matches your finding).

We're 95% confident that it's between $30,503 and $52,198

It's exactly $41,351

We're 95% confident that it's between $0 (prediction is -$25,140) and $107842

Question at position 28

28

1 point

Question 28 is unpinned. Click to pin.

Question at position 28

Which of the 4 models that you ran would you say performs the best and why?