Auniversity surveyed recent graduates of the english department about their starting salaries. four hundred graduates returned the survey. the average salary was $25,000. assume for purposes of this problem that the population standard deviation is known, and it is $2,500. what is the 95% confidence interval for the mean salary of all graduates from the english department?

Okay so for every triangle has three angles that always add up to 180 degrees. and to tell the difference between whether they are secure, right or obtuse is that acute: has one angle that is less than 90 degrees. right triangle means there is at least one angle that is exactly 90 degrees. and an obtuse angle has an angle that is bigger than 180 degrees. i’ll do #13 as an example: 13. 40 and 50 so if every triangle has 180 degrees 40+50= 90 degrees then180-90= 90 degrees so the third angle is 90 degrees and because this triangle has a 90 degree angle it means it is a right triangle