Which of the following is a good survey? You survey every 10th student entering school to find out the amount of time it takes them to get to school.
You survey the football team to determine if the school should purchase a new weight bench for the recreation room.
You survey every 10th person at the mall to determine the most popular hobbies of teenagers.

Evaluate cos2θ for cosθ = square root of 3/2

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.

Fred has a spinner that is split into four equal sections: red, blue, green, and yellow. fred spun the spinner 688 times. which of the following would be a good estimate of the number of times the spinner lands on the green section? a. 269 b. 603 c. 344 d. 189