Question: Let x be a random variable that represents the ph of arterial plasma. For healthy adult, the mean of the x distribution is u = 7.4. A new drug for arthritis has been developed. However it is thought that this drug may change blood ph. A random sample of 31 patients with arthritis took the drug for 3 months. Blood tests shoed the average ph to be \(\bar{X}\) = 8.1 with sample standard deviation s= 1.9.Use a 5% level of significance to test the claim that the drug has changed (either way) the mean ph level of the blood.