It must be a classmate of yours who asked a similar question over in the welding & bolting forum. Look there.
This isn't really supposed to be a "do my homework for me" forum, but on the other hand this isn't exactly textbook information...I'm all for giving students a grip on reality. As long as there aren't 30 students from the same class all asking the same question!
Shop welding is always cheaper and easier and higher quality than field welding. Steel errectors like bolted connections. Field weld when required such as moment connections or for items such as roof truss to shoe connections. Welders have to lug around heavy welding cables and steel errectors have bags of bolts. If you are installing steel in cold weather, then the shrink of the steel can make bolting difficult. Try a means guide to get an "idea" of bolt/welding hours required....adjust hours as required
There’s some steel supply, fabrication and erection cost information in the Australian Steel Institute publication Costing of Steelwork from Feasibility to Completion (Steel Construction; Vol 30, No 2, 1996;