# ps 1 solution - Chemistry420 Problemset#1 Noname,nograde ....

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Chemistry 420 Problem set #1 Due at the beginning of class September 15 No late assignments will be accepted. No name, no grade. Show all of your work for each answer. Partial credit will be given and NO credit will be awarded if no work is shown. Be careful to use correct significant figures. 1. (10 points) Last season, University of Illinois running back Rashard Mendenhall had rushing efforts of: 33, 139, 150, 214, 76, 160, 67, 85, 189, 201, 88, 124, and 155 yards. Calculate the mean and standard deviation of Mendenhall’s yards per game performance. (2 pts for setting up mean, 2 pts for correct mean value, 3 pts for setting up SD, 2 pts for correct SD, 1 pt for reasonable significant figures) 1 33 139 150 214 76 160 67 85 189 201 88 124 155 129 13 N i i x x N = ++++ ++ + +++ == = () ( ) ( ) ( ) ( ) ( ) 2 222 2 22 2 222 1 33 129 139 129 150 129 214 129 76 129 160 129 67 129 85 129 189 129 201 129 88 129 124 129 155 129 1 12 N i i xx s N = −+−+−+−+ −+−+ −+ −+−+−+ −+−+− 9216 100 441 7225 2809 961 3844 1936 3600 5184 1681 25 676 37698 56 12 12 s + + + + + + + = Mendenhall’s average yards per game = 129 ± 56 Acceptable answers= 129 ± 56, 130 ± 60, 129 ± 56.0 2. (10 points, Skoog 1 10) The data in the table below were obtained during a colorimetric determination of glucose in blood serum. Glucose concentration (mM) Absorbance, A 0.0 0.0002 2.0 0.150 4.0 0.294 6.0 0.434 8.0 0.570 10.0 0.704 a. Assuming a linear relationship, find the least squares estimates of the slope and intercept. (4 points; 1 point for Excel plot or worksheet, 1.5 pts for each value) b. Use Excel to find the standard deviations of the slope and intercepts. What is the standard error of the estimate? (2 points) c. Determine the 95% confidence intervals for the slope and intercept. d. A serum sample gave an absorbance of 0.350. Find the glucose concentration and its standard deviation. (4 pts: 2 pts for setting up equation, 0.5 pts for reasonable error propagation, 0.5 pts for significant figures, 1 pt for final value)

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a) slope = 0.0701, intercept = 0.0083 b) stdev slope = 0.0007, stdev intercept = 0.0040 c) N/A d) () sample sample sample
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ps 1 solution - Chemistry420 Problemset#1 Noname,nograde ....

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