0the data set with the results of a test for 1000 students is approximated by a bell curve.
the mean score was 72%. the standard deviation was 7%. based on this information, what is the best approximation for the number of students who scored 80% or better?
16
159
309
800

An automated water dispenser fills packets with one liter of water on average, with a standard deviation of 5 milliliter. the manual says that after a year of operation the dispenser should be tested to see if it needs recalibration. a year later a number of filled packets are set aside and measured separately. it is found that the average packet now contains about 0.995 liters. does the dispenser need calibration? explain your answer.

The parabola x = y² - 9 opens: a.)up b.)down c.) right d.)left

Factor the expression using gcf 9b+45