document.write( "Question 1204650: 1. The nine items of a sample had the following values: 45, 47, 50, 52, 48, 47, 49, 53, 51. Does the mean of the nine items differ significantly from the assumed population mean 47.5? (a = 0.05) \n" ); document.write( "
Algebra.Com's Answer #841043 by Theo(13342)\"\" \"About 
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find the mean and standad deviation of the sample.
\n" ); document.write( "i get meqan = 49.1111 and standard deviation = 2.6914
\n" ); document.write( "standard error = standard deviation / sqrt(sample size) = 2.6914 / sqrt(9) = .8971
\n" ); document.write( "t-score = (x-m)/s = (49.1111 - 47.5) / .8971 = 1.7959.
\n" ); document.write( "area under normal distributuion curve to the right of that t-score with 8 degrees of freedom = .0551
\n" ); document.write( "two tailed critical p-factor on each end of 95% confidence interval = .025.
\n" ); document.write( "this is higher than that, indicating the resuls are not significant.
\n" ); document.write( "there is not enough information to say that the population mean is not what is claimed to be.
\n" ); document.write( "i solved this with my ti-84 plus calculator and confirmed the answer through the use of the online statistical calculator at https://www.statskingdom.com/130MeanT1.html
\n" ); document.write( "here are the results from that calculator.\r
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\n" ); document.write( "\n" ); document.write( "the results indicae that the p-value is 10.22.
\n" ); document.write( "the p-value i got from my ti-84 plus was .0511.
\n" ); document.write( "the .0511 p-value i got was for the high end tail of the confidence interval.
\n" ); document.write( "that would be alpha/2.
\n" ); document.write( "alpha is therefore twice that = 10.22
\n" ); document.write( "the critical alpha is .05 on both tails.
\n" ); document.write( "that's .025 for each tail.
\n" ); document.write( "when comparing p-values, you would either compare .0511 to .025 or .1022 to .05.
\n" ); document.write( "either way, the test p-value is higher than the critical p-value by a fairly wide margin.
\n" ); document.write( "the results from the online calculator tell you that the 95% confidence interval is 47.0977 to 51.1245.
\n" ); document.write( "49.1111 is within tht interval, indicating the results are not significant at .05 two tailed significance level.\r
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