An Estimation of the Total Number of Texas Fishermen,1 September 1978-31 August 1979
The Texas Parks and Wildlife Department mailed 2 different survey questionnaires to 5,000 randomly selected households to estimate the number of residents fishing and the ways they fished in Texas from 1 September 1978 through 31 August 1979. The questionnaires in this survey were identical except one sub-group (1000) asked household members questions regarding their possession of a valid fishing license. Differences in responses to these 2 questionnaires were used to assess response biases. Estimates of total license sales (a known statistic) from survey data showed a strong positive bias...