To determine who would be considered unemployed when calculating the unemployment rate, we need to identify individuals who are actively seeking work but do not currently have a job.
- The 18-year-old electrician working full time but wanting more hours is not considered unemployed, as he is already employed.
- The 15-year-old girl who wants to work part-time but is unable to find work is not counted as unemployed since she is not actively seeking a job (assuming she's not of legal working age in many regions).
- The 65-year-old retired plumber who has no interest in looking for new work is also not considered unemployed, as he is not in the labor force.
- The 22-year-old teacher who recently lost his job and is actively looking for a new one is considered unemployed, as he is part of the labor force and seeking work.
Therefore, the individual considered unemployed is:
A 22-year-old teacher who recently lost his job and is currently looking for a new one.