Livestock Disease Surveys: A Field Manual for Veterinarians

abattoir surveillance animal sampled animals in population binomial distribution brucellosis CHANCES OF DETECTING Cluster sampling confidence interval confidence level desired confidence of detecting correction factor detect any positives detecting at least Detecting the Presence disease is present Disease Prevalence Epidemiology estimate Example Expected proportion false negative false positive finite population found clean n/N gives the width herds or flocks hypergeometric distribution least one positive level of occurrence LIMITS FOR NUMBER Livestock Disease Surveys Manual for Veterinarians microbial culture Monitoring Multistage Sampling number of animals number of foetal number of males number of positives number sampled period prevalence point prevalence population given positive result predictive value prevalence of disease proportion negative proportion of positives proportion were tested ratio sample size required select a random sensitivity and specificity sheep simple random sample specified proportion Stratified Sampling Systematic sampling table gives test to give total population two-digit random numbers upper limit width of confidence