Dr. toris wants to test an incentive program designed to increase attendance in her classes. for the first 8 weeks of the semester, she does not use the program and records attendance rates each week. then she institutes the incentive program for the last 8 weeks and continues to record attendance rates each week. she detects an increase in attendance over the last 8 weeks. this is an example of which experimental design?

Avegetable garden and a surrounding path are shaped like a square that together are 11ft wide. the path is 2ft wide. find the total area of the vegetable garden and path

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.

Adecibel is a logarithmic unit that can be used to measure the intensity of a sound. the function y = 10logx gives the intensity of a sound in decibels, where x is the ratio of the intensity of the sound to a reference intensity. the reference intensity is generally set at the threshold of hearing. use the graphing utility to graph the decibel function.a whisper has a sound intensity of 30 decibels. use your graph to you complete the following statement. the sound intensity of a whisper is times the reference intensity.