Engineering Economy and statistics

Assignment 9 Due: Wed. Nov 28, 2018 Stevens - Fall 2018

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CEE 4200 -- Assignment 9 Due: Wed. Nov 28, 2018

In Chapter 11: 11.8, 11.12, 11.33, 11.38, 11.54

In Chapter 13: 13.7, 13.14, 13.20, 13.26, 13.53

Stats 9.1

In a study of a concrete curing improvement process for prestressed beams, the following data were collected to determine the effect of curing time and temperature on the compression strength of the concrete. The equation is . Here are the data. From these data, do the following:

• Plot the data as you see fit • Determine the regression coefficients using Data/Data Analysis/Regression in Excel

(see note on using Excel for regression analysis) • The standard deviation of those coefficients • Comment on your solution • If the cost of increasing the temperature by 10oC is $10/yard3, what is the 1) increase

in strength relative to standard conditions and its standard deviation, and the cost and its standard deviation for 100 yard3 for using warmed concrete with a 3 day cur- ing time.

Time.hours Temperature.C

Change in compressive strength relative to 48 hrs and 25 oC, 'S (ksi)

Replicate 1 Replicate 2 Replicate 3 5 10 -0.1471 -0.1418 -0.1011 5 20 -0.0852 -0.0713 0.0210 5 30 -0.0128 -0.0206 -0.0088 5 40 -0.0850 -0.0719 -0.0336 50 10 -0.0927 -0.0421 -0.0813 50 20 0.0662 -0.0442 -0.0460 50 30 0.1621 0.1440 -0.0437 50 40 0.0211 0.2021 0.0918 150 10 -0.0170 -0.1928 -0.2181 150 20 -0.1307 -0.0494 -0.1452 150 30 0.0629 0.1731 0.1078 150 40 0.3068 0.2875 0.2440 500 10 -0.3633 -0.4950 -0.6253 500 20 -0.0801 -0.0329 -0.0516 500 30 0.4625 0.5223 0.5030 500 40 0.9109 0.9574 0.8996

S' E0 E1 Time 48–� � E2 Temperature 25–� �+ +=