REGION III
ANNAPOLIS FIELD OFFICE
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EPA Report Collection
Information Resource Center
US EPA Region 3
Philadelphia, ?A 13107
US. EPA ANNAPOLIS FIELD OFFICE, ANNAPOLIS SCIENCE CENTER, Annapolis, Md. 21401
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I. INTRODUCTION
The Annapolis Field Office began using pumps to obtain dissolved
oxygen samples during water quality surveys in 1967. Testing of
results obtained at the time indicated that the pumps were sufficiently
accurate for use in the surveys. Furthermore, tests on submersible
pumps reported in the literature supported this conclusion., Two
types of pumps have been used by AFO crews to sample for dissolved
oxygen: the Rule Master 1300 (submersible, push) and the Teel 1P580
(mounted, pull).
During the August 1975 Delaware Intensive Survey, the AFO loaned
the Philadelphia Water Department a Rule Master high speed pump.
Following this survey, the Water Department performed a series of tests
comparing DO samples from the Rule Master pump and DO samples by an
2
APHA sampler. These tests indicated that their pumped samples had
been significantly aerated at DO levels between 1 and 6 mg/1
(corresponding to DO deficits between 2 and 7 mg/1). It was not
determined whether the aeration resulted from improper use of the pump.
Common errors include failure to completely clear the pump hose before
filling the DO bottle, failure to adequately restrict the flow from
the high speed pump hose thus allowing splashing in the DO bottle,
and failure to allow water in the DO bottle to overflow 2-3 volumes
before capping. It was recommended that AFO review its sampling
procedure and conduct a similar study.
The mention of trade names or commercial products in this report
is for illustration pruposes and does not constitute endorsement or
recommendation by the U. S. Environmental Protection Agency.
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II. THEORETICAL CONSIDERATIONS
First, the potential sources of extraneous oxygen in the pumps
were considered. For a submerged pump, such as the Rule Master,
aeration could result from (1) transient air initially caught in the
pump and hose, (2) splashing of the sample stream in the DO bottle,
or (3) air leaks in the hose. The first problem should be eliminated
by clearing the lines by pumping through at least three gallons of
water before taking a sample. The second problem should be eliminated
by crimping the hose to reduce the velocity of the stream, by inserting
the hose well into the DO bottle, and by allowing the DO bottle to
overflow three volumes before removing the hose and capping. The
third problem should be eliminated by regular inspections of the hose.
All of these problems, then, should be controllable.
For a surface mounted pump, such as the Tee!, the same potential
problems and solutions are applicable. In addition, however, is the
potential introduction of air through the pump itself during operation.
This could result from a loose casing and/or extra strain on the pump
caused by excessive crimping of the hose (by restricting the flow of
water through the apparatus, the volume displacement pump could pull
air through the casing). This problem should be minimized with careful,
experienced handling and periodic inspections of the pump.
If aeration is occurring due to faulty pumps or handling
techniques, the amount of dissolved oxygen added to the sample should
be proportional to the partial pressure gradient in the gas phase and
-------
3
the concentration gradient in the liquid phase. This is similar
to reaeration in streams described by the following equation:
dC A
j j_ ~ PM T7 \ ^c- "~ ^ /
at L V S
where
K[_ = the interfacial oxygen transfer coefficient
A = surface area through which transfer occurs
V - volume of the sample
C = saturation value of DO
C = concentration of DO in the sample
The oxygen transfer coefficient itself is a function of the diffusivity
of oxygen in water D^ and the rate of surface renewal r, itself a
function of flow regime:
The terms describing the gas phase and air-water interface are usually
lumped in a volumetric coefficient Ka, which is a weak function of
temperature:
K
Naj
where e = 1.025 (1.016 - 1.040).
Thus, for a constant temperature,
"l* — i/ / r r\
jJt Ka \^s ~ LJ'
and, over a small period of contact time,
A DOD = Ka x DOD x At,
-------
where DOD is the DO deficit of the water being sampled, C - C.
Assuming a constant volumetric oxygen transfer rate K and contact
time t, then the dissolved oxygen deficit of the sample DOD should
be related to the deficit of the water by
DOD = DOD (1-K At).
s a
As one consequence of this relationship, a linear regression of DOD
versus DOD should give an intercept of 0 and a slope less than or
equal to 1.0. Because K is a positive exponential function of
a
temperature, DOD versus DOD should yield progressively smaller slopes
at higher temperatures. Variations in pump operation would probably
mask this effect in experimental situations, however, allowing the
grouping of data taken throughout a moderate temperate range.
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III. EXPERIMENTAL PROCEDURE
The subsequent steps were followed during all experiments
reported in this paper.
1. A plastic 75 gallon drum was filled with tap water.
2. Oxygen was monitored with a YSI submergible probe,
YSI 5419, and a model 51 A YSI meter. The
YSI equipment had been previously calibrated using
the azide modification of the Winkler dissolved
oxygen method, APHA 1975, pp. 143-4484.
3. An A. H. Thomas 8590-H20 stirrer was employed to
maintain an adequate current for the YSI probe and
to minimize a dissolved oxygen gradient. Homogeneinty
of this system was established in a preliminary exper-
iment in which 24 samples were siphoned from the
drum and assayed (Appendix A).
4. Prepurified nitrogen and/or oxyqen v.»as bubbled through the drum
using a gas dispersion tube, Kimax 28630, until the
desired D.O. was obtained.
5. Stirring was maintained and the temperature was recorded.
6. The Rule Master 1300 or the Tee! 1P580 pump line
was placed in the drum and three gallons of water were
pumped out to free the lines of entrapped air.
7. The delivery hose of the pump was crimped to restrict
the flow from the pump until splashing was minimized.
8. The hose was placed at the bottom of a 300cc BOD
type bottle. Twelve bottles were over filled with
approximately three times their volume. This was
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achieved by filling the bottles over an empty plastic
bucket of predetermined volume.
9. The pump was stopped and twelve replicate bottles
were siphoned from the tank using tygon tubing
(1/4" O.D.)- Over-filling was not deemed necessary
since the flow was very slight and no splashing was
observed.
10. All bottles v/ere capped after being filled and
immediately "fixed" as outlined in APHA 1975, p. 443.
11. All samples were immediately assayed using a Fisher Model 41
Auto Titralyzer. Fisher P-340, 0.025 N Potassium
Biodate was used as the primary standard and twenty
duplicate biodate standards were used to establish
the precision of this instrument, (Appendix A).
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RESULTS AND DISCUSSION
Prior to experimentation with the pumps, the precision of
both the analytical method and of the siphoning procedure was determined.
Twenty replicates of 0.025M Potassium biodate standards were run on
o
a Fisher Titralyzer, giving a variance of 0.0025 (mg/1) DO (S = .05 nig/1).
Twenty-four replicate samples were siphoned from the tank, giving a
variance of 0.0049 (mg/l)2DO (S - .07 mg/1). Thus the variance added by
siphoning alone was approximately twice the variance due to the analytical
procedure. Assuming perfect accuracy in sampling and analysis,
95 of 100 siphoned samples should lie within — 0J2 mg/1 from the
correct value. Both the analytical procedure and the siphoning technique
were considered precise enough to proceed with the experiments.
Nine experiments at DO levels ranging from 1.1 - 5.6 mg/1 (DOD
from 4.5 - 9.1 mg/1) were run by an AFO chemist, to compare the samples
collected by the Rule Master pump with those obtained by siphoning.
Nine similar experiments were performed with the Teel pump at DO
levels from 1.0 - 5.0 mg/1 (DOD from 4.1 - 8.8 mg/1). [To check the
sensitivity to technique involved in sampling, the following pump
operators were tested: A field technician and an AFO chemist not
experienced in the operation of the pump; and an experienced field
technician.] Twelve replicates from the pump and the siphon were
analyzed during each experiment. Variances were tested for homogeneity
using the F-test at the
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TABLE 1
Summary of Experiments
Number
Instrument
Ope'rator Rep!
Rule Master
operated
by lab
chemist.
Tot or Avg.
Teel
operated
by lab chemist
Tot or Avg.
Teel operated
by inexper.
field tech.
Tot or Avg.
Teel operated
by exoer.
fiela tech.
Tot zr Avg.
of
icates
12/12
12/12
11/12
12/12
12/12
12/12
12/12
12/12
12/11
12/12
12/12
12/12
12/12
12/12
12/12
12/12
12/12
12/12
12/12
12/12
12/12
12/12
Siphon
DO
(mg/1)
5.6
5.6
4.5
3.3
3.1
2.6
2.3
1.1
1.2
3.1
2.7
1.0
5.0
3.1
1.6
1.8
1.9
1.7
Temp
(Q C)
15
15
16
15
15
15
16
15
14
16
16
16
17
11
17
11
16
16
Siphon
DOD
(mg/1)
4.5
4.5
5.4
6.8
7.0
7.5
7.6
9.0
9.1
6.8
7.2
8.9
4.7
7.9
8.1
9.2
8.0
8.2
Pump
DOD
(mg/1)
4.5
4.5
5.0
6.7
6.9
7.5
7.6
9.0
9.0
5.7
7.1
8.8
4.1
7.1
7.7
8.2
8.1
8.2
Homogeneous Equal
Variance Means
(a = .01) (a - .01)
/ /
/ /
x1
/ /
/ /
/ X
/ /
/ /
/ X
8 6
X
X
X
0
X
X
Y « —
V — . _
0
/ /
/ /
2 2
Prob of not det
0.1 mg/1 dif.(e)
(a = .01)
.07
.07
—
.11
.17
.05
0
.31
.12
.11
__
—
—
—
—
--
--
—
—
.36
.07
.21
In this first experiment performed,
cleared before sampling.
the pump line was not sufficiently
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The probability of not detecting a mean difference of 0.1 mo/1 (the 3-error)
was computed from the sample size, pooled standard deviation, and the
a level (.01). Data from each experiment are listed in Appendix A,
and a summary is provided in Table 1.
Of the nine experiments on the Rule Master pump operated by a
laboratory chemist, all but the first passed the test for homogeneous
variances. In the first experiment, the pump line was not sufficiently
cleared before sampling, and aeration of the samples occurred due to residual
air in the pump and hose. In subsequent experiments at least 3 gallons of
water were pumped through the hose before collecting sameles. Subject to
adequate clearing of the hose, the Rule Master pump is a sufficiently precise
sampling instrument.
Eight experiments with the Rule Master pump and the siphon were tested
for equality of means. Although two experiments did result in statistically
significant differences, the average differences were all less than 0.1 mg/1.
The probability of not detecting a 0.1 mg/1 difference in means averaged 11%.
A linear regression between pumped D.O. deficits (DODp) and siphoned deficits
(DODs) gave a slope of .991, an intercept of 0.063 mg/1 DODp and a correla-
tion coefficient exceeding 0.999. It is concluded that, with adequate handling,
the Rule Master pump is a sufficiently accurate sampling instrument.
Of the nine experiments on the Tee! pump, seven were operated by
inexperienced operators, and none of these seven experiments passed the
test for homogeneous variances. In two of these experiments, the average
differences between pump and siphon were 0.08 and 0.11 mg/1, respectively
giving marginally unacceptable accuracies. Generally, however, the Teel
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pump with inexperienced operators is neither a sufficiently precise nor
sufficiently accurate sampling instrument.
The two experiments on the Teel pump with an experienced operator
passed both the test for homogeneous variances and the test for equal
means. Average differences between pump and siphon were 0.0 and 0.03 mg/1,
respectively. In the latter experiment, both the precision and the accuracy
of the pump seemed to exceed that of the siphon. The Teel pump with an
experienced operator, then, can be both a sufficiently precise and sufficiently
accurate sampling instrument.
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CONCLUSIONS
1. The Rule Master pump is sufficiently precise and accurate to use
for sampling D.O. at deficits as high as 9 mg/1 (this covers all D.O.
concentrations at temperatures exceeding 20°C, and down to 1 mg/1 D.O.
at 15°C).
2. The Tee! pump can be operated by experienced personnel in a manner
sufficiently precise and accurate to use for sampling D.O. at deficits
as high as 8 mg/1.
3. The Teel pump operated by inexperienced personnel can result in imprecise
and inaccurate D.O. measurements.
4. The Rule Master pump is preferable to the Teel pump because it is less
sensitive to variations in operating procedures.
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REFERENCES
1. Whaley, R. C., "A Submersible Sampling Pump," Limnology and Ocenography,
Vol. 3, No. 4, October, 1958.
2. Blair, D. D., "Statistical Analysis of Two Dissolved Oxygen Sampling
Procedures", Technical Report prepared by the Philadelphia Water Depart-
ment, December 10, 1975.
3. O'Connor, D. J. et al, "Mathematical Modelling of Natural Systems," notes
for a course given in May, 1975.
4. Standard Methods for the Examination of Hater and Vlastewater, 14th Edition,
American Public Health Association, Inc., 1975.
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APPENDIX A
EXPERIMENTAL DATA AND STATISTICS
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Preliminary Experiment: Uniform D.O.
Twenty-four D.O. bottles were siphoned from the tank and assayed via the
Azide-Modification of the Winkler Method,APHA 1975 pp. 443-448. The
following D.O. concentrations (ppm) were obtained:
4.3 4.2
4.3 4.2
4.2 4.1
4.2 4.1
4.1 4.1
4.3 4.1
4.2 4.2
4.1 4.1
4.2 4.1
4.2 4.2
4.2 4.1
4.1 4.1
N = 24
S = 0.07
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Preliminary Experiment: Precision of Fisher Auto Titralyzer
Twenty duplicate standards were prepared using: 10 ml of 0.025 N Potassium
biodate, 284 ml of distilled water; 2 ml of cone. ^$04; 2 ml of APHA*
Manganese sulfate; and 2 ml of APHA* Alkali-iodide-Azide reagent. These
standards were titrated using the Fisher model 41 titralyzer and the follow-
ing concentrations (ppm) were obtained:
4.9
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.1
5.0
5.0
5.0
5.0
4.9
5.0
4.9
4.9
with N = 20 and S = 0.05
* APHA 1975, p. 443
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Experiment 1
Dissolved Oxygen Range 4.3 - 5.6 mg/1
Temperature 16°C
Rule Master Pump
4.7
5.6
5.0
4.9
5.0
4.7
4.7
4.7
4.8
4.8
4.7
H0: a
X"-| =4. 87 3
a = .01
4.5
4.5
4.5
4.3
4.5
4.4
4.4
4.5
4.4
4.5
4.5
4.4
n2=12
X2=4.467
S22=.00455
Fa = 4.23
Chemist 2/23
F = 15.8641 Reject - Variances are not homogeneous
X1 - X2 = 4.87 - 4.47 * 0.40
Comments :
Pump line not completely cleared before running experiment (only 1 gal water
running experiment (only 1 gal water was pumped prior to experiment)
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Experiment 2
Dissolved Oxygen Range 2.5 - 2.7 mg/1 Chemist 3/17
Temperature 15°C
Rule Master Pump Siphon
2.6 2.6
2.6 2.5
2.7 2.5
2.7 2.5
2.6 2.6
2.6 2.5
2.6 2.6
2.5 2.6
2.6 2.6
2.6 2.5
2.6 2.6
2.6 2.5
n2 = 12 ri] = 12
X2 = 2.608 X-j = 2.55
S2, = .00265 S? = .00273
HQ: ff-,2 = a22 a = .01 Fa = 4.47
r- Si? _ 1.0292 Accent - variances are homogeneous
F =-^2 -
b2
H0 = y-| - y2 = 0 a = .01 Ta = 2.508
T = 2.7529
Reject - there is a significant difference between means
IT] - )T2 = 2.61 - 2.55 - 0.06
nl n
!- n-| t n2 , where 6 = the mean difference
to be detected = 0.1 mg/1
d* = .9848 6 = .05
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Experiment 3
Dissolved Oxygen Ranae 1.1 - 1.4 mg/1 Chemist 3/17
Temperature 14°C
Rule Master Pump Siphon
1.2 1.2
1.3 1.2
1.3 1.1
1.3 1.1
1.3 1.1
1.2 1.3
1.4 1.3
1.3 1.2
1.3 1.2
1.2 1.2
1.3 1.2
1.3
n2 = 12 m = 11
X"2 = 1.2833 JTj = 1.1909
= .00334 S? = .00491
Hn: °1 CT2 a = -01 Fa = 4'23
\J *—
F = 1.4714 Accept - variance are homogeneous
HQ: ji-| - U2 - 0 a = .01 Ta = 2.518
T = 3.4643
Reject - there is a significant difference in means
jf| - X"2 = 1.28rl .19 = 0.09
d* = .7993 3 = .12
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Experiment 4
Dissolved Oxygen Range 5.5 - 5.7 mg/1 Chemist 4/2
Temperature 15°C
Rule Master Pump Siphon
5.6
5.5
5.6
5.6
5.6
5.6
5.7
5.7
5.7
5.6
5.5
5.6
n1 = 12
X"-, = 5.6083
S2 = .00447
2 2
HQ: a-] = 02 a = .01
5.5
5.7
5.6
5.6
5.6
5.6
5.6
5.7
5.6
5.6
5.6
5.6
n2 = 12
X~2 - 5.6083
s| = .00265
Fa = 4.47
F = 1.6849 Accept - variance are homogeneous
HQ: y-j - y2 = ° a = .01
T - 0 Accept - no signi
Ta = 2.508
ficant difference in me.
X"-, - 5f2 = 5.61 - 5.61 - 0
d* = .8561 8 - .07
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Experiment 5
Dissolved Oxygen Range 5.5 - 5.7 mg/1 Chemist 4/2
Temperature 15°C
Rule Master Pump Siphon
5.6
5.6
5.6
5.6
5.6
5.6
5.7
5.6
5.7
5.6
5.5
5.7
n2 = 12
JT2 = 5.6167
9
S2 = .00333
5.7
5.6
5.6
5.6
5.6
5.6
5.7
5.6
5.5
5.6
5.6
5.5
n1 = 12
X"-, = 5.6
Sf - .00364
H0: a-,2 = a22 a = .01 Fa = 4.47
F = 1.9309 Accept - variance are homogeneous
H0: ui - P£ = ° a = .01 Ta = 2.508
T = .6934 Accept - no significant difference in means
Jf-j - J2 = 5-62 - 5-60 = -n2
d* = .8658 3 = .07
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Experiment 6
Dissolved Oxygen Range 2.2 - 2.4 rng/1
Chemist 4/2
Temperature 16°C
Rule Master Pump
2.3
2.3
2.3
2.4
2.3
2.3
2.3
2.3
2.3
2.3
2.3
2.3
n2 = 12
X~2 - 2.3083
5? = .000833
Siphon
2.3
2.3
2.2
2.3
2.2
2.3
2.3
2.3
2.3
2.3
2.3
2.3
n1 = 12
X"-j = 2.2833
S2 - .00152
HQ: °-i2 = o22 a = .01 Fa - 4.47
F = 1.8182 Accept - variances are homogeneous
HQ: u-j - u2 = 0 a = .01 Ta = 2.508
T = 1.7868 Accept - no significant difference in means
X"-, - X"2 = 2.31 - 2.28 = .03
d* = 1.4905 3=0
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Experiment 7
Dissolved Oxygen Range 0.9 - 1.2 mg/1 Chemist 4/2
Temperature 15.5°C
Rule Master Pump Siphon
1.0 1.1
1.1 1.0
1.1 1.0
1.1 1.2
1.1 1.1
1.0 1.2
1.0 1.0
1.1 1.1
1.1 1.0
1.0 1.2
1.1 0.9
1.2 1.0
n2 = 12 n-j = 12
X"2 = 1 .075 X"-, - 1 .0667
$2 = .00386 S2 - .0097
HQ: 0^ = az2 a = .01 Fa = 4.47
F = 2.5098 Accept - variances are homogeneous
H0: y-| - y2 = 0 a = .01 Ta = 2.508
T = .2479 Accept - no significant difference in means
X"-] - X"2 = 1.08 - 1.07 - . 01
d* = .6203 3 = .31
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Experiment 8
Dissolved Oxyqen Range 3.0 - 3.2 ing/1 Chemist 1/4
Temperature 15°C
Rule Master Pump Siphon
3.0
3.2
3.1
3.1
3.2
3.2
3.1
3.2
3.2
3.2
3.2
3.2
n2 = 12
X~2 = 3.1583
S2 ^ .00447
HQ : 0-| = o"2 a - .
F = 1.1525 Accept
U] - y2 ~ 0 a ~
T = 1 .4685 Accept
3.1
3.2
3.1
3.1
3.2
3.1
3.1
3.0
3.1
3.2
3.2
3.0
PI = 12
X] - 3.1167
S2 = .00515
01 Fa = 4.47
- variances are homogeneous
.01 Ta = 2.508
- no significant difference in means
H0:
X"-, - X"2 = 3.16 - 3.12 = .04
d* - .736 3 - .17
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Experiment 9
Dissolved Oxygen Range 3.2 - 3.4 tng/1
Chemist 4/4
Temperature 15 C
\\r
;1
2 =
Rule Master Pump
3.3
3.3
3.4
3.4
3.5
3.4
3.3
3.3
3.4
3.4
3.4
3.4
n2 = 12
X"2= 3.375
s| - .00386
a - .01
Siphon
3.3
3.2
3.3
3.3
3.4
3.4
3.3
3.3
3.4
3.3
3.4
3.4
n-| - 12
X"i = 3.3333
S| = .00424
Fa = 4.47
F = 1.0984 Accept - variances are homogeneous
H0: y-| - y2 = 0 a = .01 Ta = 2.508
T - 1.6041
Accept - no significant difference in means
- X" = 3.38 - 3.33 = .05
2
d* = .8026 3 - .11
-------
Experiment 10
Dissolved Oxygen Range 3.1 - 3.2 mq/1 Chemist 3/26
Temperature 16°C
Teel Pump Siphon
4.9
5.3
4.5
4.5
-5.9
5.1
3.2
3.3
3.3
3.7
3.2
3.7
= 12
4.2167
1815
3.2
3.1
3.2
3.1
3.1
3.1
3.1
3.1
3.2
3.2
3.1
3.1
n2 = 12
JT2 = 3.1333
9
$2 = .00242
H0: a-|2 = a22 a = .01 Fa - 4.47
F = 364.2562 Reject - variances are not homogeneous
X"-, - X~2 = 4.22 - 3.13 - 1 .09
-------
hxperimsnt M
Dissolved Oxygen Range 2.6 - 2.8 mg/1 Chemist 3/26
Temperature 16°C
Tee! Pump Siphon
2.7 2.7
2.6 2.8
2.7 2.7
2.7 2.7
2.6 2.7
2.6 2.7
2.7 2.8
2.7 2.6
2.8 2.7
2.7 2.7
3.3 2.7
3.3 2.6
n] = 12 n2 = 12
X"-, - 2.7833 X~2 = 2.7
S2 = .0615 S2 = .00364
H0: a-|2 = a22 a = .01 Fa - 4.47
F = 16.8956 Reject - variances are not homogeneous
X"i - X"2 = 2.78 - 2.70 = 0.08
-------
Experiment 12
Dissolved Oxygen Range 0.9 - 1.2 mg/1
Temperature 16°C
Pumo
n-| = 12
X-, = 1.1417
- .06629
Siphon
1.1
1.1
1.0
1.0
1.0
1.1
1.9
1.2
1.0
1.0
1.0
1.3
1.0
1.2
1.2
1.0
0.9
1.0
1.0
1.1
1.0
0.9
1.0
1.0
n9 = 12
X2 = 1.025
= .00932
Chemist 3/26
2 9
H0: a-, = a2
F = 7.1127
a = .01
Fa - 4.47
Reject - variances are not homogeneous
X, - A-, = 1 .14 - 1.03 = 0.11
-------
Experiment 13
Dissolved Oxygen Range 4.9 - 5.1 mgl
Temperature 17°C
Teel Pump
HQ: a-,2 = a22
a - .01
F = 451.8113 Reject
X] - X"2 = 5-55 ~ 5-01 =
Inexperienced Field Technician 4/1
S-'nhon
4.9
6.1
8.3
7.1
5.5
5.0
5.0
5.0
4.9
4.9
4.9
5.0
n-| - 12
Xi = 5.55
S2 = 1.1973
5.0
5.0
5.1
5.0
5.0
4.9
5.1
5.0
5.0
5.0
5.0
5.0
n2 =
Xj? = 5
S2 -
on — .
12
.0083
00265
Fa = 4.47
variances are not homogeneous
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Experiment 14
Dissolved Oxygen Range 3.0 - 3.3 mg/1 Inexperienced Field Technician 4/1
Temperature 11 °C
Tee] Pump Siphon
4.9
4.8
4.2
3.5
3.7
3.8
4.1
3.4
3.7
3.4
3.3
3.5
= 12
: 3.8583
3.2
3.2
3.0
3.1
3.2
3.3
3.0
3.0
3.3
3.0
3.0
3.0
n2 = 12
X~2 = 3.1083
S2 = .2899 S| - .0154
HQ: a-]2 = a22 a = .01 Fa - 4.47
F = 18.8247 Reject - variances are not homogeneous
JTj - Jf2 = 3.85 - 3.11 = 0.74
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Experiment 15
Dissolved Oxygen Range 1.8 - 1.9 mg/1 Inexperienced Field Technician 4/1
Temperature 11 °C
Tee! Pump Siphon
3.7 1.9
2.8 1.9
2.6 1.8
1.9 1.8
1.8 1.9
1.9 1.9
1.8 1.8
1.8 1.8
2.6 1.8
1.9 1.8
1.8 1.9
1.8
ni =12 n2 = 12
X"-, = 2.2 X"2 = 1.8455
S2 = .3636 s| - .00273
H0: a-,2 = a22 a = .01 Fa = 4.4
F = 133.2 Reject - variances are not homogeneous
I-! - I2 = 2.20 - 1.85 - 0.35
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Experiment 16
Dissolved Oxygen Range 1.5 - 1.7 mg/1 Inexperienced Field Technician 4/1
Temperature 17.5°C
Tee! Pump Siphon
5.4
4.6
4.2
1.7
1.9
1.6
2.3
2.2
2.2
1.6
1.6
2.0
= 12
1.5
1.5
1.6
1.7
1.5
1.5
1.5
1.6
1.6
1.6
1.7
1.6
n2 = 12
X] = 2.6083 X2 = 1.575
= 1.7699 S2 = .00568
H0: a-,2 = az2 a = .01 Fa = 4.47
F = 311.5024 Reject - variances are not homogeneous
jf-| - X"2 = 2.61 - 1.58 = 1 .03
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Experiment 17
Dissolved Oxygen Range 1.6 - 1.8 nig/1 Experienced Field Technician 4/2
Temperature 16.5°C
Teel Pump
X-] = 1 .7083
= .00447
Siphon
1.6
1.8
1.8
1.7
1.7
1.6
1.7
1.8
1.7
1.7
1.7
1.7
= 12
1.7
1 .6
1.7
1.7
1.8
1.7
1.7
1.7
1.7
1.8
1.7
1.7
n2 = 12
X2 - 1.7083
= .00265
V
H0:
a-, = a2
F = 1.6858
vn - Uo = o
a = .01 Fa - 4.47
Accept - variances are homogeneous
a = .01 Ta - 2.508
T = 0 no significant difference
X] - X2 = 1-71 - 1.71 - 0
d* = .856
6 = .07
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Experiment 18
Dissolved Oxygen Range 1.8 - 1.9 mg/1 Experienced Field Technician 4/2
Temperature
Teel Pump Siphon
2.0
2.0
1.9
1.8
1.8
1.7
1.9
1.9
1.8
1.7
1.8
1.7
1.9
1.8
1.8
1.9
1.8
1.8
1.9
1.9
1.9
1.9
1.8
1.9
-12 n? = 12
X] = 1.8333 X2 - 1.8583
S^- = .0115 s| = .00265
H0: a-!2 = 022 a = .01 Fa = 4.47
F = 4.3396 Accept - variances are homogeneous
H0: ui - y2 = Q a = .01 Ta = 2.508
T = .728 Accept - no significant difference in means
X-] - X2 = 1 .83 - 1 .86 = 0.03
d* = .607 3 - .36
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