An industrial firm supplies 10 independent manufacturing plants with a certain chemical. The probability that any one of the firm calls in an order on a given day is 0.2 and this probability is the same for all ten plants. 

1. Find the probability that, on a given day, the number of plants calling in orders is at most three? 

2. Find the probability that, on a given day, the number of plants calling in orders is at least three? 

3. Find the probability that, on a given day, the number of plants calling in orders is exactly three?

4. Find the expected number (mean) and standard deviation of the manufacturing plants calling in an order in a given day?