In a study at West Virginia University Hospital, researchers investigated smoking behavior of cancer patients to create a program to help patients stop smoking. They published the results in Smoking Behaviors Among Cancer Survivors (January 2018, Journal of Oncology Practice). In this study, the researchers sent a 22-item survey to 1,333 cancer patients. They collected demographic information (age, sex, ethnicity, zip code, level of education), clinical and smoking history, and information about quitting smoking. Of the 1,333 patients who were mailed surveys, 267 patients responded. For various reasons, researchers used only 240 of the completed surveys. 35 out of 126 female cancer patients reported being past smokers, and 72 out of 114 male cancer patients reported being past smokers. Calculate the difference between the corresponding sample proportions P1 - P2 (female minus male). Important: Round the final answer to 4 decimal places