Here is the histogram of a data distribution. All class widths are 1. Which of the following numbers is closest to the mean of this distribution?

Polygons efgh and e′f′g′h′ are shown on the coordinate grid: what set of transformations is performed on efgh to form e′f′g′h′? a. a translation 1 unit to the left followed by a 90-degree counterclockwise rotation about the origin b. a translation 1 unit to the right followed by a 90-degree counterclockwise rotation about the origin c. a 90-degree clockwise rotation about the origin followed by a translation 2 units to the right d. a 90-degree clockwise rotation about the origin followed by a translation 2 units to the left

An energy drink company claims that its product increases students' memory levels. to support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory. the missing component in this study is a .

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.