The lengths of text messages are normally distributed with a population standard deviation of 3 characters and an unknown population mean. If a random sample of 24 text messages i taken and results in a sample mean of 27 characters, find a 99% confidence interval for the population mean. Zo.10Z0.0520.025 Zo.01 Z0.005 1.282 1.645 1.960 2.326 2.576 You may use a calculator or the common z values above. Select the correct answer below: a.(26.21,27.79) b.(25.99.28.01) c.(25.93,28.07)

Jacob signs up to work for 2 1/2 hours at the school carnival. if each work shift is 3/4 hour, how many shifts will jacob work? (i just want to double check : |, for anybody that responds! : )

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

1- is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis. 2- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis. 3- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in part b?