1. The number of pounds of steam used per month by a chemical plant is thought t
ID: 3228879 • Letter: 1
Question
1. The number of pounds of steam used per month by a chemical plant is thought to be related to the average ambient temperature (in oF) for that month. The past years usage and temperature are shown in the following table: Jan. Feb. Mar Apr May Sune July Aug Sept od Nov. Dec Sum A Minitab Regression output of the steam usage data is: Regression Analysis: Usage/1000 versus Temp. Model Summary R-sq R-sq (adj) R-sq(pred) 1.94284 99.999% 99.999% 99.98% Coefficients Coef SE Coef T Value P-Value Term Constant -6.34 1.67 3.80 0.003 Temp 1.00 9.2084 0.0338 272.64 0.000 Regression Equation Usage/1000 -6.34 9.2084 Temp.Explanation / Answer
d) Esimate of mean steam usage when average temperature is 55o F
by putting value in regression equation we can get this value
Mean steam usage/ 1000 = -6.34 + 9.2084 * Temp. = -6.34 + 9.2084 * 55 = 500.122
Mean steam usage = 500122 pound steam
(e) Fitted value of y for APril month where average temperature value was 47o F
Mean steam usage/ 1000 = -6.34 + 9.2084 * Temp. = -6.34 + 9.2084 * 47= 426.4548 pound steam usage/1000
Residual = observed value - predicted value = 424.84 - 426.45 = -1.61 pound steam usage/1000
(f)
As slope of regression is positive so we can say that higher average temperature will lead to higher steam usage.
Here minitab output shows T - value = 272.64 that shows that P - value = 0.000 that means for alpha = 0.01 it is under signiificant level so we can say that slope coefficient B1 is not equal to 0.
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