Germination of sunflower seeds The germination rate of a particular seed is the percentage of seeds in the batch which successfully emerge as plants. Assume that the germination rate for a batch of sunflower seeds is $80 \%,$ and that among a large population of $n$ seeds the number of successful germinations is normally distributed with mean $\mu=0.8 n$ and $\sigma=0.4 \sqrt{n} .$
a. In a batch of $n=2500$ seeds, what is the probability that at least 1960 will successfully germinate?
b. In a batch of $n=2500$ seeds, what is the probability that at most 1980 will successfully germinate?
c. In a batch of $n=2500$ seeds, what is the probability that between 1940 and 2020 will successfully germinate?