The average age of a breed of dog is 19.5 years. If the distribution of their ages is normal and 20% of dogs are older than 22.6 years, find the standard deviation.

Consider the image seen here. the image, at point y, represents the process of during which a is being produced.

Which of the following is a characteristic of the coverdell education savings account

On a test the graders have a mean of 77 and a standard deviation of 8. if we can approximate the distribution of these graders by a number distribution what percent of the students. a) scores higher than 77? b) should pass the test (grades > 60)? c) should fail the test (grades < 60)?