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Inputting the Toluca Company data.
input x y 80 399 30 121 50 221 90 376 70 361 60 224 120 546 80 352 100 353 50 157 40 160 70 252 90 389 20 113 110 435 100 420 30 212 50 268 90 377 110 421 30 273 90 468 40 244 80 342 70 323 end label var x "lot size" label var y "work hrs"
Figure 2.2 on page 51.
reg y x
Source | SS df MS Number of obs = 25
-------------+------------------------------ F( 1, 23) = 105.88
Model | 252377.581 1 252377.581 Prob > F = 0.0000
Residual | 54825.4592 23 2383.71562 R-squared = 0.8215
-------------+------------------------------ Adj R-squared = 0.8138
Total | 307203.04 24 12800.1267 Root MSE = 48.823
------------------------------------------------------------------------------
y | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
x | 3.570202 .3469722 10.29 0.000 2.852435 4.287969
_cons | 62.36586 26.17743 2.38 0.026 8.213711 116.518
------------------------------------------------------------------------------
90% CI for beta0, page 54.
regress y x, level(90)
Source | SS df MS Number of obs = 25
-------------+------------------------------ F( 1, 23) = 105.88
Model | 252377.581 1 252377.581 Prob > F = 0.0000
Residual | 54825.4592 23 2383.71562 R-squared = 0.8215
-------------+------------------------------ Adj R-squared = 0.8138
Total | 307203.04 24 12800.1267 Root MSE = 48.823
------------------------------------------------------------------------------
y | Coef. Std. Err. t P>|t| [90% Conf. Interval]
-------------+----------------------------------------------------------------
x | 3.570202 .3469722 10.29 0.000 2.975536 4.164868
_cons | 62.36586 26.17743 2.38 0.026 17.5011 107.2306
------------------------------------------------------------------------------
Confidence intervals X = 100, pages 60 & 65.
set obs 26
replace x = 100 in 26
regress y x in 1/25
predict yhat2
predict stdf, stdf
predict stdp, stdp
generate ll1 = yhat2 - 1.714*stdp
generate ul1 = yhat2 + 1.714*stdp
generate ll2 = yhat2 - 1.714*stdf
generate ul2 = yhat2 + 1.714*stdf
list ll1 ul1 ll2 ul2 in 26
ll1 ul1 ll2 ul2
26. 394.9233 443.8488 332.2006 506.5715
Figre 2.6, page 69.
graph twoway (lfitci y x, level(90) ciplot(rline) )
Example of correlation coefficient and R-squared, page 82.
corr y x
(obs=25)
| y x
-------------+------------------
y | 1.0000
x | 0.9064 1.0000
regress y x
Source | SS df MS Number of obs = 25
-------------+------------------------------ F( 1, 23) = 105.88
Model | 252377.581 1 252377.581 Prob > F = 0.0000
Residual | 54825.4592 23 2383.71562 R-squared = 0.8215
-------------+------------------------------ Adj R-squared = 0.8138
Total | 307203.04 24 12800.1267 Root MSE = 48.823
------------------------------------------------------------------------------
y | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
x | 3.570202 .3469722 10.29 0.000 2.852435 4.287969
_cons | 62.36586 26.17743 2.38 0.026 8.213711 116.518
------------------------------------------------------------------------------
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