A lab technician is using this exponential model, ​A(t)= 100e​ -0.8t ​to measure cells in a petri dish over a period of hours. (2 pts each) a. After several hours, would there be ​more​ cells or ​fewer​ cells in the petri dish?​ ​(circle one)

b. How many cells would there be after 10 hours? ​(round to the nearest hundreths)​

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.