# 12 - Due: Sunday, December 9, 2007 11:59 PM EST...

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Due: Sunday, December 9, 2007 11:59 PM EST Current Score: 30 out of 30 Question Score Submission Options Description Homework #12 covers scatterplots, correlation, and least squares lines. Instructions Homework #12 You are allowed 4 submissions for most problems; you are allowed only 2 submissions for some of the multiple choice questions. This homework is worth 30 points. The due date is 11:59pm Sunday, Dec. 9. DO NOT WAIT UNTIL THE LAST MINUTE TO START THIS HOMEWORK! 1. 3/3 points Last Response | Show Details All Responses Notes Make a scatterplot of the following data: x 1 2 3 4 10 10 y 1 3 3 5 1 11 Question 1 . Use your calculator or software to calculate the correlation (use 4 decimal places in your answer) 0.4811 .4811 (use 4 decimal places in your answer) Question 2 . What feature of the data reduces the correlation despite the straight-line association between x and y in most of the observations? (_) (_) Two of the observations have a y -coordinate equal to 3.

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(_) (_) There is not enough spread in the first four observations. (_) (_) Most of the x -values are too small. (o) (o) The presence of an outlier reduces the correlation. Question 3 . When viewing the scatterplot, one point stands out as an outlier that deviates from the overall pattern of the plot. Remove this point from the data and re-calculate the correlation (use 4 digits in your answer) 0.9925 .9925 2. 4/4 points Last Response | Show Details All Responses Notes
Here are four scatterplots labeled Plot A, Plot B, Plot C, Plot D. The calculated correlations are (in no particular order) -0.923, -0.487, 0.006, 0.777. Match the values of the correlations with the scatterplots (don't guess; 2 submissions allowed). (i) . -0.923 is the correlation of Plot d D -or- d . (ii) . -0.487 is the correlation of Plot b B -or- b .

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(iii) . 0.006 is the correlation of Plot a A -or- a . (iv) . 0.777 is the correlation of Plot c C -or- c . 3. 1/1 points Last Response | Show Details All Responses Notes Roller coasters get all their speed by dropping down a steep initial incline, so it makes sense that the height of the drop might be related to the speed of the coaster. Here's an Excel file of the top speed and largest drop for 75 roller coasters around the world. Shown below is a scatterplot with largest drop , in feet, on the x axis, and speed, in miles per hour, on the y axis. Calculate the correlation between drop and speed (use 3 decimal places in your answer). 0.910 .909695
4. 3/3 points Last Response | Show Details All Responses Notes The SAT and ACT are the two major standardized tests that colleges use to evaluate applicants. Most students take just one of these tests. However, some students take both. This Excel file gives the scores of 60 students who took both tests. Can we relate the two tests? Plot the data with SAT on the x axis and ACT on the y axis and answer the questions below. Question 1 . What is the correlation between the SAT and ACT scores?

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This note was uploaded on 03/22/2008 for the course BUS 350 taught by Professor Reiland during the Spring '08 term at N.C. State.

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# 12 - Due: Sunday, December 9, 2007 11:59 PM EST...

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