. As the confidence level increases margin of error . The correlation coefficient (r) is a number between and . For testing Ho: p = 0.45 versus Ha: p . 0.45, the test statistic value is 1.84. What is the p-value? . A study has been published linking radon gas, which is commonly found in houses constructed near limestone, to increased brain-cancer rates. The study also stated that radon gas levels above 3.0 pCi/L are considered to be harmful. Their Ho: H = 3 versus Ha: H > 3. For a specific house, the test conclusion was not to reject the null hypothesis. However, in reality in that house, the radon gas level was 4.0 pCi/L. This conclusion is classified as a error. . A study is conducted to evaluate the mathematics proficiency of middle school students of a large northern Virginia school district. There are 21 middle schools in the district. The Education board randomly selects 4 schools and test mathematics proficiencyes of all 2977 students attending those 4 schools. The sampling method is used in this study