Before data is entered into the regression calculator, some data may be excluded. Explain why the data pair (0, 100) was excluded for the comparison of hours slept the night before and the test score. Describe what this data point represents. If it was included, would the trend line describe the data well?

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.