Dataset:  fluorescent_lamp.dat

Source: F.G. Rosillo and N.M. Chivelet (2009). "Lifetime Prediction of Fluorescent Lamps
Used in Photovoltaic Systems," Lighting Research and Technology, Vol. 41, #2, pp.183-197.

Description: Nonlinear regression, relating the ratio of observed to nominal lifetime for fluorescent
lamps (Y=LT/LT_0) to integrated glow current (X1= I_glow) and the 
ratio of observed to nominal voltage (X2=V_lamp/V_lampnom).
Y = observed lifetime/advertised lifetime
X1 = a measure of gas discharge
X2 = observed voltage/advertised voltage (measure of performance of lamp and ballast)

Model: Y = 1/(1+b0+b1*X1+b2*X2+b3*(X2^2))  + error

Variables/Columns
Model    7-8
Type    9-16  /* F=Tube/Wattage/Diameter   C=Compact/watts
#Lamps (sample size)  24
LT/LT_0 = Y   26-32
I_glow = X1   33-40
V_Lamp       42-48
V_Lampnom    50-56