This randomizer works for everyone from toddlers to elders. This will change your sim characters and give them much more depth. Turn on the testing cheats and use this code:

stats.set_stat lifeskillstatistic_

Directly after the underscore, type one of the character values (the two-worded ones should be entered as one word, no space). Then, type a space and your number value. The range is from -100 to 100. If your sim is an adult and falls on the high side in either direction (90 or above), don't forget to equip them with the extra trait to go with it.