Table h. — Test IIB conducted in Harris River for a distance of 

 8,000 feet, September 2, 1957 



Observer 



Section 2 



Pools Riffles 



Section 3 



Pools Riffles 



Section h 



Pools I Riffles 



Total for 

 stream 



^ standard deviation. 



^ Coefficient of variation (in percent), 



Table 5. 



-Test lie conducted in Harris River for a distance of 

 8,000 feet, September 11, 1957 



Section 2 



Pools I 



Riffles 



Section 3 



Pools Riffles 



Section h 



Pools Riffles 



Total for 

 stream 



Standard deviation 



Coefficient of variation (in percent) 



Variability of estimates was again high in 

 pools in section 2 and was also high in riffles 

 in section 3. It is difficult to explain why ob- 

 server 9 saw no fish in section 3, particularly 

 since section division points were well marked. 

 Apparently this was an error on the part of 

 the observer. 



Differences in variation between pool and 

 riffle estimates by three observers in par- 

 ticular sections on September 2 and 11 appear 

 random. 



Tests IIA, IIB, and IIC all involved more 

 than two observers. Four additional tests, 

 IID, HE, IIF, and IIG, were made to compare 

 one observer's estimate with another's. 

 Variability between observers in these tests 



is apparent (table 6). Data were analyzed on 

 the bases of significance of differences of 

 means and by analysis of variance. In some 

 instances difference between means of ob- 

 servers was significant, in others not. Anal- 

 ysis of variance showed a significant dif- 

 ference between observers in only one test, 

 IID, The degree of variation is more apparent 

 from the data in table 6 than it would be from 

 analyses of variance of the data, and there- 

 fore no analyses are presented. 



Evaluation and Recommendation 



Variability between different observers 

 estimating numbers of live pink salmon was 

 higher under normal than under ideal condi- 

 tions. Under normal conditions variability 



