Scientists measured the size of Dungeness crab shells over a 10 year period from 1982 to 1992, both in
nature and in the laboratory
x = premoult (before shedding) shell size (mm)
y = postmoult (after shedding) shell size (mm)
This bivariate data set was modelled using a linear
least
squares regression line 9=0.9056x+26.729
with a correlation coefficient of r = 0.990.
Predict the value of a postmoult shell in mm, given
that premoult shell size was 90 mm.

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)