An entomology PhD student is studying rare spider species. She would like to determine the population density of the spider in a particular region in South Dakota. She sets out 20 traps in randomly selected locations within the specified region during a period of time when the spiders have been known to be active in similar regions. After a two-week period, she returns to the traps and finds no spiders. Estimate the probability of finding a spider in this region using a 95% confidence interval.