The scatter diagram show the cost (in pounds) and length of trip (in days) for the business trips taken by the employees (A to H) of a certain firm last year.

a) Two of the trips were abroad. Identify, with reasons, the two employees who made these trips

A regression of cost on length of trip is found

b) Explain the significance of the gradient and intercept of this line in terms of trip costs, giving examples to illustrate your answer.