A new electronic device for measuring blood pressure is introduced in the market. An experiment has been conducted to compare the precision (measurement variation) of measurements taken by the new device with those taken by the doctors (with their own existing devices). Three devices (of the new product) are randomly selected from a store and three doctors are randomly selected from a large pool of doctors. One patient’s blood pressure has been monitored for 15 days and on each day the blood pressure was read by all three devices and all three doctors. (see data below)

(a) Using a one-way random effects model, analyze the blood pressures measured by the devices. In your analysis, include an ANOVA table, F-test, estimate of the mean blood pressure, estimates of the two variance components, and a 95% confidence interval for the mean blood pressure. Interpret your results.

(b) Repeat the above analysis for the blood pressures measured by the doctors.

(c) How does the device compare to doctor readings of blood pressure?

data:

Reading by Devices Reading by Doctors Day Devi Dev2 Dev3 Day Docl Doc2 Doc3 1 133.34 133.36 133.45 1 126.54 127.36 131.88 2 110.94 110.85 110.92 2 124.69 128.86 132.39 3 118.54 118.56 118.67 3 125.46 129.43 134.43 4 137.94 137.80 137.77 4 125.95 130.72 134.28 5 139.52 139.62 139.59 5 125.90 130.13 134.44 6 139.23 139.11 139.36 6 127.85 132.03 137.37 7 117.96 117.81 117.85 7 125.55 132.05 132.17 8 119.59 119.42 119.48 8 125.80 129.87 134.97 9 116.12 116.00 115.93 9 125.11 128.09 133.97 10 128.38 128.48 128.41 10 125.75 131.94 132.68 11 125.17 125.25 125.34 11 128.77 130.05 134.75 12 134.62 134.41 134.55 12 125.26 131.13 134.29 13 136.14 136.07 136.22 13 126.26 130.91 133.38 14 131.21 131.03 130.96 14 125.68 128.83 135.67 15 132.51 132.86 132.65 15 124.47 129.46 134.39