4. About 1 in 3 US. adultsas estimated 68 millionhave high blood pressurel, which increases the risk for heart disease and stroke, leading causes of death in the United States. High blood pressure is called the "silent killer" because it oen has no warning signs or symptoms, and many people don't realize they have it. That's why it's important to get your blood pressure checked regularly. But is the rate of US. adults really this high? Another web site claims that the true percentage of US. adults with high blood pressure is actually dramatically lower than 1 in 3 (33.3%). To test this claim we randomly selected 500 adults across the US. and found that 165 of them had high blood pressure. (Use a 1% signicance level.)