Q2 Z2,(Q2) Z2(Q2) - Institute for Water Resources - U.S. Army

. The coefficients of the dummy variables for towboat age in the
towboat cost regression do indicate that the very oldest boats are
less efficient than the newest boats. Boats built prior to 1950 are
approximately 17% more costly to operate than the newest boats. Boats
built between 1950 and 1955 are 4% more costly to operate, although
the coefficient of the 1950-55 dummy variable is not significant. How-
ever, for boats built between 1956 and 1960, the results indicate a
reduction in operating cost of 9% over the newest boats. The latter
coefficient is also not significant.
A dummy variable for the Kort nozzle was included in both the
towboat cost and towboat production functions. For the combined log
regressions of the towboat production function, Kort nozzles improved
average productivity by more than 26% for-both upstream and downstream
movements. Both coefficients are significant. The Kort nozzle coef-
ficients are positive for all six of the individual company log regress-
.
ions. Four of the six coefficients are significant. The range of
improvement for the individual companies is from 14% to 41%. The linear
regressions indicate that Kort nozzles may be slightly more important
for downstream movements.
Supporting evidence of Kort nozzles is obtained from the towboat
cost function. Here, the Kort nozzle coefficient is negative and
significant. A 15% reduction in average towboat cost is indicated for
. use of the Kort nozzle.
As reported in Chapter Iv, an attempt was made to measure capital
embodied technological change for the barpequipment.. Both a linear
age index and dummy variables for age groups were tried. F-tests per-
formed on these variables indicated that no significant cost differences
145