The academic discipline of Statistics is a branch of mathematics that develops and uses techniques for the careful collection, effective presentation, and proper analysis of numerical information. These techniques can be applied to find answers to questions that arise in all areas of human endeavor. Medical researchers use them to test the safety and effectiveness of new drugs or to appraise the effects of lifestyle changes; nutritionists use them to investigate health claims associated with foods or dietary supplements; business executives use them to assess the results of marketing campaigns or the effect of new methods of production on product quality. Economists use them to forecast the business cycle; politicians to predict the outcome of future elections. Spies use them decipher coded messages. The list goes on. No wonder that Statistics has been called a universal guide to the unknown. Consider your own health, just one among millions of topics that Statistics could address. Every day we meet new health-related stories ̶ about prescription and over-the-counter drugs, medical devices and procedures, the lifestyle we should adopt, foods we should favor, and dietary supplements that would surely add years to our lives. Rightly, we dismiss many of these stories as pure snake oil. Mayonnaise prevents Alzheimer’s? Chelation therapy blasts away arterial plaque? Food coloring lowers bad cholesterol? Cinnamon clobbers diabetes? Grapefruit erases breast cancer? Watermelon slashes prostate cancer? Come on! But what about more serious-sounding claims? True enough, reports about ACE inhibitors and beta blockers, Advil and Motrin, 64-slice CT scans and PSA tests, drug-coated stents and the DASH diet appear to be far removed from snake oil, but false claims about any of these may well occur, which makes them snake oil no less than those absurd and fantastic claims about mayonnaise and Alzheimer’s. Or consider how glowing press releases of one time, even by renowned medical journals or the Food and Drug Administration, are often followed later by conflicting stories, which makes us ask: Will fancy cholesterol drugs save us from heart attacks or will they destroy our liver? Is the once-a-day baby aspirin the “cure of the century” or a stroke-causing hoax? Will Avandia fight our diabetes or give us a heart attack? A knowledge of Statistics offers a remedy: If we care to separate bogus claims from the real thing, we must adopt the special way of statistical thinking that is routinely employed by the best of those who undertake the scientific studies that alone can generate medical knowledge we can trust.Learning Statistics, therefore, is well worth it, but it is not easy. The field is so vast that no single book can reasonably cover all of it. Nor can it anticipate which topics will be of interest to any given person or group of them. This author, therefore, has divided the field into 24 sections that are made available as separate electronic books from which prospective students and teachers can select the subset that is most useful to them. In this tenth book of the series you will learn about the nature of continuous random variables and their probability distributions, called probability density functions. Among other things, you will learn about useful applications based on 1. the standard normal curve, 2. exponential probabilities, and 3. uniform probabilities.And here is a typical problem you will be able to solve: The miles per gallon (mpg) rating of all the registered cars in the nation is a normally distributed random variable with a mean of 25.9 and a standard deviation of 2.45. An automobile manufacturer wants to build a car with an mpg rating that improves upon 99 percent of existing cars. What must the new car's mpg rating be?"To facilitate your studies, this book contains numerous similar problems as well as True-False, Multiple-Choice and other tests, along with all their answers.