document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1077671>Question 1077671</A>: <I><SPAN STYLE=\"word-break: break-all;\"> P value tcdf(2.45,99,10) not working<BR>\n" );
document.write( "REM (rapid eye movement) sleep is sleep during which most dreams occur. Each night a person has both REM and non-REM sleep. However, it is thought that children have more REM sleep than adults†. Assume that REM sleep time is normally distributed for both children and adults. A random sample of n1 = 11 children (9 years old) showed that they had an average REM sleep time of x1 = 2.5 hours per night. From previous studies, it is known that &#963;1 = 0.6 hour. Another random sample of n2 = 11 adults showed that they had an average REM sleep time of x2 = 1.70 hours per night. Previous studies show that &#963;2 = 0.9 hour. Do these data indicate that, on average, children tend to have more REM sleep than adults? Use a 1% level of significance.<BR>\n" );
document.write( "(a) What is the level of significance? <BR>\n" );
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document.write( ".01<BR>\n" );
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document.write( "Correct: Your answer is correct.<BR>\n" );
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document.write( "State the null and alternate hypotheses.<BR>\n" );
document.write( "H0: &#956;1 = &#956;2; H1: &#956;1 < &#956;2<BR>\n" );
document.write( "H0: &#956;1 = &#956;2; H1: &#956;1 &#8800; &#956;2    <BR>\n" );
document.write( "H0: &#956;1 = &#956;2; H1: &#956;1 > &#956;2<BR>\n" );
document.write( "H0: &#956;1 < &#956;2; H1: &#956;1 = &#956;2<BR>\n" );
document.write( "Correct: Your answer is correct.\r<BR>\n" );
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document.write( "(b) What sampling distribution will you use? What assumptions are you making?<BR>\n" );
document.write( "The Student's t. We assume that both population distributions are approximately normal with known standard deviations.<BR>\n" );
document.write( "The standard normal. We assume that both population distributions are approximately normal with unknown standard deviations.    <BR>\n" );
document.write( "The standard normal. We assume that both population distributions are approximately normal with known standard deviations.<BR>\n" );
document.write( "The Student's t. We assume that both population distributions are approximately normal with unknown standard deviations.<BR>\n" );
document.write( "Correct: Your answer is correct.\r<BR>\n" );
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document.write( "What is the value of the sample test statistic? (Test the difference &#956;1 &#8722; &#956;2. Round your answer to two decimal places.) <BR>\n" );
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document.write( "2.45<BR>\n" );
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document.write( "Correct: Your answer is correct.<BR>\n" );
document.write( " \r<BR>\n" );
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document.write( "(c) Find (or estimate) the P-value. (Round your answer to four decimal places.) <BR>\n" );
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document.write( ".0171<BR>\n" );
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document.write( "Incorrect: Your answer is incorrect.<BR>\n" );
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document.write( "THank you! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #692126 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=692126\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This is a one way test, so the p-value calculated is half of what is found using the value of the test statistic.  For a test stat of 2.45, which I do get, there is a p-value of 0.0142 using a two way test (equal, not equal) and 0.0071 (0.007083983 is the calculator output)using a one way test. </SPAN>\n" );
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