An iq test is designed so that the mean is 100 and the standard deviation is 12 for the population of normal adults. find the sample size necessary to estimate the mean iq score of statistics students such that it can be said with 95% confidence that the sample mean is within 2 iq points of the true mean. assume that sigma=12 and determine the required sample size.

we're not supposed to use graphic calculators and while i got how to find z, i'm having trouble figuring out how i'm supposed to find e without n?

The price of an item has been reduced by 30%. the original price was $30. what is the price of the item now ?

Can someone me out here number 4 plz

Michelle and julie work at a catering company. they need to bake 264 cookies for a birthday party that starts in a little over an hour and a half. each tube of cookie dough claims to make 36 cookies, but michelle eats about 1/5 of every tube and julie makes cookies that are 1.5 times as large as the recommended cookie size.it takes about 8 minutes to bake a container of cookies, but since julie's cookies are larger, they take 12 minutes to bake. a. how many tubes should each girl plan to bake? how long does each girl use the oven? b. explain your solution process what did you make? c. what assumptions did you make?