Discussion:
Q: The Sunbeam Corporation makes a wide variety of appliances for the home. One product is a digital blood pressure gauge. For obvious reasons, the blood pressure readings made by the monitor need to be accurate. When a new model is being designed, one of the steps is to test it. To do this, a sample of people is selected. Each person has his/her systolic blood pressure taken by a highly respected physician. They then immediately have their systolic blood pressure taken using the Sunbeam monitor. If the mean blood pressure is the same for the monitor as it is as determined by the physician, the monitor is determined to pass the test. In a recent test, 15 people were randomly selected to be in the sample. The blood pressure readings for these people using both methods are:
Systolic BP Systolic BP
as measured as measured
by a by Monitor
physician
112 126
109 108
139 116
141 123
120 138
99 123
128 119
118 122
116 116
120 118
111 114
123 108
114 130
121 123
132 127
a. Based on the sample data and a significance level equal to 0.05, what conclusion should the Sunbeam engineers reach regarding the latest blood pressure monitor?
b. Conduct the test as a paired t-test.
c. Discuss which of the two procedures in parts a and b is more appropriate to analyze the data presented in this problem.