Answer:
the standard deviation for the number of restaurants specializing in seafood is 0.8944
Explanation:
Given that :
Sum total number N of top restaurants in Chicago = 20
Four of the restaurants specialize in seafood,
then , the probability that a randomly selected restaurant from the top 20 in the list will specialize in seafood will be p = 4/20
p = 0.2
sample size n = 5
Assuming X to be the random variable that follows a Binomial distribution that represent the number of restaurants specializing in seafood.
Then:

where;
n = 5 and p = 0.2
The standard deviation σ can be determined by using the formula:




σ = 0.894427191
σ
0.8944