Here is a question about this article: A sample rate of 44.1 kHz is almost always used, because this is also used for CD audio, the main source used for creating MP3 files. A greater variety of bit rates are used on the Internet. The rate of 128 kbit/s is commonly used, at a compression ratio of 11:1, offering adequate audio quality in a relatively small space. As Internet bandwidth availability and hard drive sizes have increased, higher bit rates up to 320 kbit/s are widespread.
What is the answer to this question: What is the main source used for creating MP3 files?
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So... CD audio

Here is a question about this article: Popper held that rationality is not restricted to the realm of empirical or scientific theories, but that it is merely a special case of the general method of criticism, the method of finding and eliminating contradictions in knowledge without ad-hoc-measures. According to this view, rational discussion about metaphysical ideas, about moral values and even about purposes is possible. Popper's student W.W. Bartley III tried to radicalise this idea and made the controversial claim that not only can criticism go beyond empirical knowledge, but that everything can be rationally criticised.
What is the answer to this question: What type of knowledge is not the only sphere of rational criticism, according to Popper's student W.W. Bartley III?
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So... empirical

Here is a question about this article: The foundation of Northwestern University is traceable to a meeting on May 31, 1850 of nine prominent Chicago businessmen, Methodist leaders and attorneys who had formed the idea of establishing a university to serve what had once been known as the Northwest Territory. On January 28, 1851, the Illinois General Assembly granted a charter to the Trustees of the North-Western University, making it the first chartered university in Illinois. The school's nine founders, all of whom were Methodists (three of them ministers), knelt in prayer and worship before launching their first organizational meeting. Although they affiliated the university with the Methodist Episcopal Church, they were committed to non-sectarian admissions, believing that Northwestern should serve all people in the newly developing territory.
What is the answer to this question: How many founders did Northwestern University have?
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So...
nine