Twin Births. As a result of a greater number of births to older women and the increased use of fertility drugs, the number of twin births in the United States increased approximately 42% from 1990 to 2005 (National Center for Health Statistics, U.S. Department of Health and Human Services). The quartic function
f(x) = -0.056316x4 - 19.500154x3
+ 584.892054x2 - 1518.5717x
+ 94,299.1990,
Where x is the number of years since 1990, can be used to estimate the number of twin births from 1990 to 2006. Estimate the number of twin births in 1995 and in 2005.