fqll_11_Q3_answers_v2

fqll_11_Q3_answers_v2 - Answers to questions missed on quiz...

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Answers to questions missed on quiz three Question one: Given the following scenarios, in which case is the error of prediction highest? Scenario A: Among the population of one year old babies, 80% who have above average weight also have above average height and 80% who have below average weight also have below average height. This is a positive correlation; pretty high. There is some error of prediction. Scenario B: For women in the 70-80 year age range, 70% of the women who have below average bone density have above average osteoporosis and 70% who have above average bone density have below average osteoporosis. This is negative correlation, pretty high. There is some error of prediction. Scenario C. In the population of adults as the size of the wrist increases, anxiety level does not change. This is zero correlation. Error of prediction is highest. Scenario D. Keeping volume constant, 100% of the metals that have above average density also have above average mass and 100% that have below average density also have below average mass. This is perfect positive correlation r = -1 . There is no error of prediction Hint: Before picking the right answer, draw the scatterplot corresponding to each scenario. Question two What is the mean of the error in the following scenarios? Scenario A: There are 30 bothers and sisters and in all cases the age of the brother is half of the age of the sister. Perfect correlation mean of error = 0 Scenario B: SAT quantitative and verbal scores for 30 students. Positive correlation.
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This note was uploaded on 12/03/2011 for the course STATISTICS 10 taught by Professor Gould during the Fall '11 term at UCLA.

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fqll_11_Q3_answers_v2 - Answers to questions missed on quiz...

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