Researcher hypothesizes that people who listen to music via ear buds have greater hearing loss than those in the general population. On a standard hearing test, the mean () is 24.75. Higher values indicate better hearing; lower values indicate greater hearing loss or worse hearing. The researcher gave this same test to a random sample of 30 individuals who regularly use ear buds. Their average score on the hearing test is 21.57, s = 3.85. Determine if using ear buds significantly reduces hearing.

A industrial psychologist, you have been hired by a large hospital to automate the admitting procedure and reduce the admission time. Previously it took an average of 40 minutes to admit each patient, with a standard deviation of 9 minutes. With a new computerized procedure find that your automated procedure takes an average of 34.5 minutes for the 35 patients in your pilot study. Determine if the system significantly reduced admit time.

Dr. Simpson was surprised to learn that her 28 students get on average 7.2 hours of sleep per night (s=0.80). She had just read that the national average is 7 hours per night. Determine if Dr. Simpson's students get significantly more sleep than the national average.

including hypotheses, critical value, degrees of freedom, and a statement about significance.