A College Board sample estimated the standard deviation of 2016 SAT scores to be 194 points. You are researching the average SAT score. You want to know how many people you should survey if you want to know, at a 98% confidence level, that the sample mean SAT score is within 50 points of the true mean SAT score. What value for z should you use in the sample size formula?

Astudy was interested in determining if eating milk chocolate lowered someone's cholesterol levels.ten people's cholesterol was measured. then, each of these individuals were told to eat 100g of milk chocolate every day and to eat as they normally did. after two weeks, their cholesterol levels were measured again. is there evidence to support that their cholesterol levels went down? how should we write the alternative hypothesis? (mud = the population mean difference= before - after)a. ha: mud = 0b. ha: mud > 0c. ha: mud < 0d. ha: mud does not equal 0