> warehouse <- read.table("F:\\sta4210\\CH04TA02.txt",header=F,col.names=c("X","Y"))
> 
> attach(warehouse)
> 
> pdf("F:\\sta4210\\CH04TA02.pdf")
> 
> (n <- length(Y))
[1] 12
> 
> (sum_XY <- sum(X*Y))
[1] 894714
> (sum_X2 <- sum(X^2))
[1] 190963
> 
> (b1 <- sum_XY/sum_X2)
[1] 4.685274
> 
> (Y_hat <- b1*X)
 [1]  93.70548 918.31373 538.80652 234.26371 571.60344 468.52741 154.61405
 [8] 721.53221 374.82193 688.73529 852.71989 749.64386
> (e <- Y-Y_hat)
 [1]  20.2945178   2.6862743  21.1934773  10.7362945   3.3965585   6.4725889
 [7] -16.6140457   5.4677870   0.1780711 -18.7352943 -24.7198881  12.3561423
> 
> (MSE <- sum(e^2)/(n-1))
[1] 223.4236
> 
> (s2_b1 <- MSE/sum_X2)
[1] 0.001169984
> (s_b1 <- sqrt(s2_b1))
[1] 0.03420502
> 
> (b1_95CI <- c(b1-qt(.975,n-1)*s_b1,b1+qt(.975,n-1)*s_b1))
[1] 4.609989 4.760559
> 
> plot(X,Y,main="Warehouse regression Thru Origin",xlim=c(0,200),
+       ylim=c(0,1000),xlab="Work Units Performed",ylab="Variable Labor Cost")
> abline(a=0,b=b1)
> 
> warehouse.reg1 <- lm(Y ~ X -1)
> summary(warehouse.reg1)

Call:
lm(formula = Y ~ X - 1)

Residuals:
    Min      1Q  Median      3Q     Max 
-24.720  -4.020   4.432  11.141  21.194 

Coefficients:
  Estimate Std. Error t value Pr(>|t|)    
X  4.68527    0.03421     137   <2e-16 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

Residual standard error: 14.95 on 11 degrees of freedom
Multiple R-squared: 0.9994,     Adjusted R-squared: 0.9994 
F-statistic: 1.876e+04 on 1 and 11 DF,  p-value: < 2.2e-16 

> 
> 
> dev.off()
null device 
          1 
> 
>