The number of shoes a group of college students own is approximately Normally distributed with a mean of 22.1 and a standard deviation of 6.3. About what proportion of the students own between 20 and 30 pairs of shoes? Use a graphing calculator to find the answer.

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.

How do i do this activity, is appreciated

Consider circle c with angle acb measuring 3/4 radians.if minor arc ab measures 9 inches, what is the length of the radius of circle c? if necessary, round your answer to the nearest inch.