
157More on Inferential Statistics
> binom.test(5,20,p=0.2)
Exact binomial test
data: 5 and 20
number of successes = 5, number of trials = 20, p-value = 0.5764
alternative hypothesis: true probability of success is not equal to
0.2
95 percent confidence interval:
0.08657147 0.49104587
sample estimates:
probability of success
0.25
>
We get a high p-value indicating that we should not reject a 20% grass cover. In addition, the 95%
condence interval indicates that 20% is within the interval for 25% estimate in cover. In this case,
we conclude that the cover could be 20%.
For comparison, suppose we count eight sample sites covered with grass. Now
> binom.test(8,20,p=0.2) ...