A repeated-measures study is done to measure the change in IQ test scores taken on a Monday versus those taken on a Friday. There were n = 9 participants in the study. The mean difference was MD = –5 points, and the standard error for the mean difference was = 0.51. Construct a 95% confidence interval to estimate the size of the population mean difference.

Precalculus question, image attached.

An 18% discount on a watch saved a shopper $72. find the price of the watch before the discount

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?