Please answer number 1? Thank you

What is the correlation coefficient between the variables? round to three decimal places. enter your answer in the box

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.

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.