What number is half way between 17 and 18

Anyone know? will mark brainliest if you're correct!

F(x)=x^3+4 question 6 options: the parent function is shifted up 4 units the parent function is shifted down 4 units the parent function is shifted left 4 units the parent function is shifted right 4 units

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.