Starting in the 1970s, medical technology allowed babies with very low birth weight (vlbw, less than 1500 grams, about 3.3 pounds) to survive without major handicaps. it was noticed that these children nonetheless had difficulties in school and as adults. a long-term study has followed 238 vlbw babies to age 20 years, along with a control group of 238 babies from the same population who had normal birth weight. iq scores were available for 119 men in the vlbw group. the mean iq was 85.9, and the standard deviation was 14.9. the 109 men in the control group had mean iq 98, with standard deviation 15.4.

The big black bird company (bbc) has a large order for special plastic-lined military uniforms to be used in an urgent military operation. working the normal two shifts of 4040 hours each per week, the bbc production process usually produces 2 comma 6002,600 uniforms per week at a standard cost of $125125 each. 7070 employees work the first shift and 3030 the second. the contract price is $240240 per uniform. because of the urgent need, bbc is authorized to use around-the-clock production six days per week. when each of the two shifts works 7272 hours per week, production increases to 4 comma 2004,200 uniforms per week but at a cost of $160160 each.