Being an actuary, calculating statistics to determine probability and risk, is the best job to have in 2010, while working on an oil rig as a roustabout is the worst, according to a study released on Tuesday.

An actuary earns about $85,000 a year and has few physical demands, little stress, a good work environment and a positive outlook for employment and income growth, said CareerCast.com, a job search site that analyzed 200 jobs in North America.

The second-best job is software engineer, followed by computer systems analyst, biologist and historian, said CareerCast.com, which rated jobs in terms of stress, working environment, physical demands, income and hiring outlook.

Being a roustabout was rated the worst, followed by lumberjack, ironworker, dairy farmer and welder, it said. A roustabout is a dangerous job that typically pays about $31,000 a year, with high unemployment and a negative outlook for growth, the study said.

Switching to many of the best jobs would mean returning to school, said Tony Lee, publisher of CareerCast.com’s 2010 Jobs Rated Report. This is its 12th annual study. The worst jobs are “fairly miserable,” Lee said. They tend to require working outdoors regardless of the weather, have elements of physical danger and do not pay very well, he said.

“On top of that, the job opportunities are not very good so if you really want one of these jobs, you may even have difficulty finding one despite the fact that they’re dangerous, in bad conditions and don’t pay very well,” he said.

Last year, actuary placed second and mathematician first, while lumberjack ranked as the worst job.