Help!!’n.

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.

Which number line correctly shows 0.8 + 0.3?

The probability that a u.s. resident has traveled to canada is 0.18 and to mexico is 0.09. a. if traveling to canada and traveling to mexico are independent events, what is the probability that a randomly-selected person has traveled to both? (page 109 in the book may ) b. it turns out that only 4% of u.s. residents have traveled to both countries. comparing this with your answer to part a, are the events independent? explain why or why not. (page 119 may ) c. using the %’s given, make a venn diagram to display this information. (don’t use your answer to part a.) d. using the conditional probability formula (page 114 in the book) and the %’s given, find the probability that a randomly-selected person has traveled to canada, if we know they have traveled to mexico.