Second, by including the entire eligible Danish population, which is covered by a national tumor registry, the study avoids the problem of selection bias (that is, people who do not make it into your study for various reasons, including refusal).
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By the end of the study, 215 of the study participants had experienced a heart attack or other cardiovascular problem, and 325 had died from any cause.
The EU study says says the problem of limited capacity is likely to worsen because many busy airports, including London Heathrow and Paris Orly, do not plan to expand.
Carter found that his study was indicative of a more widespread problem in the United States.
Indeed that, to a lesser extent, can be a problem for any study of a human network.
To give you an idea of how widespread the problem is, a new study to be published in the Journal of Finance and Quantitative Analysis finds that option volume in a specific stock begins to surge three days before unannounced analyst upgrades or downgrades of a company.
Instead the study showed the problem came from making copies of the cancer's genetic code.
This latest study suggests that this may be less of a problem than previously thought.
Both the Credit Suisse study and the study on the economic benefits of equality avoid this problem.
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The study cited overconfidence as the root cause of the problem.
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"Part of this isn't a sport problem, part of it is a societal problem, " said Dan Gould, director of the Institute for the Study of Youth Sports at Michigan State.
To get around this potential problem, the University of Pennsylvania study only examined studies without a washout period.
The subjects of the study were asked to solve a particular problem-solving task previously used in other psychology studies researching problem solving.
He wants to see an immediate reduction in pesticide use until the effects are better understood, and is pressing for the formation of a European Union environment unit to study the problem.
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Another problem may be the size of the study: just twelve patients.
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This problem is the focus of an important new study by Demographia.
He says part of the problem is that too few people now study classical Greek, Latin or Arabic and there are not enough experts to interpret the original texts.
There had been a lot of forums and papers published, she says, but the field had been handicapped by a tendency on the part of drug companies to approach the problem on a study-by-study basis, often not following up with communities after the work is done.
His study, commissioned by the Pharmacia drugs company, suggests the problem of HAIs is a far bigger cause of bed-blocking than delayed discharges.
And even if we were able to settle upon an acceptable definition of consciousness, we really have no idea how to study the problem.
The firm's associate director, Andrew Howis, said the latest study was just one of several efforts under way aimed at tackling the problem of stray light.
And that's a problem, considering the results of the Mobile Mindset Study, a recent survey that found three out of five U.S. smartphone users don't go more than hour without checking their gadgets.
Dr. Sanjay Gupta, CNN chief medical correspondent: This study says metabolic syndrome is a problem in the United States because of the way we eat: lots of red meat, lots of processed meat, and too much fried food.
"That was actually the predominant problem in patients in our study -- 78 percent of them had health insurance, but many of them were bankrupted anyway because there were gaps in their coverage like co-payments and deductibles and uncovered services, " says Woolhandler.
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An Access Project study showed that two-thirds of people with a medical bill or debt problem went without needed care because of the associated costs.
The problem, according to a recent study and survey by Jennifer Lawless of American University and Richard Fox of Loyola Marymount University, is that so few choose to run.
C. bought a database of subprime loans from a company called Loan Performance in order to study the problem more closely, something that, apparently, no other government regulator had thought to do.
Overall, only 2.5 percent of women in the study had experienced a stroke, heart attack, or related problem.
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Fish oil capsules failed to prevent flare-ups of atrial fibrillation, a common heart rhythm problem, in a large study in 2010.
There is one problem with this interpretation of their results: the letters in the study were sent from Cambridge, Massachusetts.
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