Aproduction manager tests 10 toothbrushes and finds that their mean lifetime is 450 hours. she then designs a sales package for this type of toothbrush. it states that consumers can expect the toothbrush to last approximately 460 hours. this is an example of what phase of inferential statistics?

Which of these equations, when solved, gives a different value of x than the other three? a9.1 = -0.2x + 10 b10 = 9.1 + 0.2x c10 – 0.2x = 9.1 d9.1 – 10 = 0.2x

Astudent survey asked: "how tall are you (in inches)? " here's the data: 67, 72, 73, 60, 65, 86, 72, 69, 74 give the five number summary. a. median: 73, mean: 70.89, iqr: 5, min: 60, max: 74 b. 60, 66, 72, 73.5, 86 c. 60, 67, 72, 73, 74 d. 0, 60, 70, 89, 74, 100

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.