In this blog you will find the correct answer of the Coursera quiz Mastering Data Analysis in Excel Coursera week 2 Quiz mixsaver always try to brings best blogs and best coupon codes
1. What is one reason False Positive classifications were expensive in the Battle of Britain.
- Pilots needed more practice.
- German bombers were always present.
- German bombers would expect to be intercepted.
- Aviation fuel for fighter planes was scarce.
2. The portion of test outcomes that are True Negatives plus the portion that are False Negatives must equal:
- One, minus the classification incidence/test incidence
- The Negative Predictive Value (NPV)
- The False Negative (FN) Rate
- One, minus the condition incidence
3. Use the Cancer Diagnosis Spreadsheet to answer Questions 3 and 4.
This spreadsheet gives 10,000 pairs of scores – the level of a (fictional) cancer diagnostic protein in Column A – along with the actual condition: 1 = cancer, 0 = no cancer in Column C.
Change the cost per False Negative classification to $20,000 [cell G3]. Change the cost per False Positive classification to $1,000 [cell H3].
Question: What is the new minimum cost per event/cost per test (rounded to the nearest dollar)?
4. What is the lowest level of protein that should be classified “Positive” to achieve the minimum cost per test at the new costs per error given above?
5. Can a change in classification threshold change a diagnostic test’s True Positive Rate? Use logic – no need to calculate any numbers.
6. “Condition Incidence” is the portion of a population that actually has the Condition being studied. Can a change in threshold change the Condition incidence? Use logic – no need to calculate any numbers.
7. Does the change in threshold change the test’s “classification incidence” (also called “test incidence”)? Use logic – no need to calculate any numbers.
8. Does the change in threshold change the test’s Area under the ROC Curve? Use logic – no need to calculate any numbers.
9. Use the Forecasting Soldier Performance Spreadsheet to answer this question:
What is the False Positive Rate if we use the sum of standardized height and standardized weight as the score; and set a threshold at -1.28?
Binary Classification (graded)
1. A test for “driving while intoxicated” was given 100 times. 20 people tested were actually intoxicated, and 10 people were mis-classified as intoxicated. What would the False Positive rate be?
2. If a fire alarm malfunctions and fails to go off when there actually is a fire, that is a:
- False Negative
- False Positive
- True Positive
- True Negative
3. Use the Binary Classification Metrics Spreadsheet Definitions to answer the following:
If the “classification incidence/test incidence” is 10% for the whole population, and the true “condition incidence” is 12% for the whole population, the True Positive rate:
- must be 100%
- cannot be 100%
- can be 100%
- must be 0%
4. Use the Cancer Diagnosis Spreadsheet to answer Questions 4 to 6.
Keep the cost per False Positive test set at $500. Use MS Solver to determine the maximum cost per False Negative test that permits an average cost per test of $100.
5. Assume a cost of $15,000 per False Negative (FN) and $100 per False Positive (FP). What is the minimum average cost per test?
6.If, instead of assuming a cost $15,000 per FN and $100 per FP, the costs are assumed to be $7,500 per FN and $50 per FP, what changes?
- The minimum cost threshold of 16,551.930
- The True Positive Rate
- The False Positive Rate
- The minimum Cost per Test
7. Use logic and the definition in the Binary Performance Metrics Spreadsheet to answer the following question.
In general, increasing the cost per FN while keeping the cost per FP constant will cause the cost-minimizing threshold score to:
- Stay the Same
8. Make a copy of the Bombers and Seagulls Spreadsheet to answer questions 8-10.
Modify the spreadsheet data so that there are 4 bombers instead of 3, and 16 seagulls instead of 17, by changing the actual condition for the radar score of 66 from a 0 to a 1 in cell D43.
What is the new Area Under the Curve:
9. Assuming the costs for classification errors are 5 million pounds per FN and 4 million pounds per FP, how much does changing the value at Cell D43 from 0 to 1 change the minimum cost per event?
- Increases by 950,000 pounds
- Increases by 5 million pounds.
- Increases by 250,000 pounds
10. Change the cost per FN to 50 million pounds. How does changing the data in cell D43 from a 0 to a 1 change the cost-minimizing threshold?
- Decreases it from 75 to 66.
- Decreases it from 75 to 62
- Decreases it from 75 to 70
- Increases it from 66 to 75.
11. Use the Binary Performance Metrics Spreadsheet definitions to answer the following question.
A population tested for “driving while intoxicated” has a Condition incidence of 20%. If the test has a true positive rate of 70% and a false positive rate of 10%, what is the test’s Positive Predictive Value (PPV)?
12.Use the Soldier Performance Spreadsheet to answer question 12.
Rank the outcomes using soldier’s age as the score, with the oldest at the top. A threshold of 24 years represents what point on the ROC Curve?
- .33, .67
- .67, .33
- .5, .5
- .25, .75
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