调查抽样理论的一个重要目标是当可靠的辅助信息(auxiliary information)可用时，利用其提高有限总体参数估计的精度。为满足估计量效率的需求，本研究在简单随机抽样(simple random sampling without replacemen 调查抽样理论的一个重要目标是当可靠的辅助信息(auxiliary ...

Learn about genicular artery embolization, a new minimally invasive procedure that is giving patients with knee osteoarthritis years of pain relief without surgery. For millions of people living with ...

"Don't judge a book by its cover," they say, but how can one not? The cover's right there. Uncovered is a website that forces the issue by presenting book excerpts without the cover-or the author, or ...

More than half of global GDP depends on nature – yet wildlife is disappearing at an alarming rate. Freshwater species have fared worst of all, with populations down 85 per cent since 1970. The ...

DEAR DR. ROACH: My 83-year-old sister underwent the simple procedure of replacing her pacemaker battery. She’s also been diagnosed with early signs of dementia. They gave her propofol, and when she ...

In his decades-long career in tech journalism, Dennis has written about nearly every type of hardware and software. He was a founding editor of Ziff Davis’ Computer Select in the 1990s, senior ...

There’s nothing quite like a free sample. Not only do you get to enjoy a new product, but it’s a great budget hack. From food to beauty products, free samples allow you to try something out to make ...

Your body is about 70% water, and staying hydrated helps maintain electrolyte balance, regulate blood pressure, lubricate joints, and support cell health. Simple strategies to drink more water include ...

The next generation is ready, but the present isn’t done. The soccer world has been preparing for life after Lionel Messi for several years now. Not because he isn’t still electrifying or because he ...

A technique that supersizes cells to reveal minute details has gone big — really big. Using a polymer similar to those used in nappies to make them super-absorbent, scientists have expanded the volume ...

Summer has well and truly arrived across the UK, and while most of us are revelling in the glorious sunshine and clear blue skies, being stuck indoors and battling the stifling heat is far from ...