document.write( "Question 1025445: an economist claims that the mean family income of a certain populated area in metro manila at most is 22,450.00 a year.
\n" ); document.write( "test the claim at 0.05 level of significance the economics students take a sample of 150 families obtaining a mean of 19,769.00 with standard deviation of 529.00 what is the conclusion
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claim is that the mean family income is at most 22,450 per year.\r
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\n" ); document.write( "\n" ); document.write( "sample taken.
\n" ); document.write( "mean of sample is 19769.
\n" ); document.write( "standard deviation of sample is 529.
\n" ); document.write( "sample size is 150.\r
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\n" ); document.write( "\n" ); document.write( "standard error is equal to standard deviation divided by square root of sample size.\r
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\n" ); document.write( "\n" ); document.write( "standard error is therefore equal to 529 / sqrt(150) = 43.19 rounded to 2 decimal places.\r
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\n" ); document.write( "\n" ); document.write( "sample mean is 19769.
\n" ); document.write( "standard error of the mean, which is also referred to as the standard deviation of the distribution of sample means, is equal to 43.19.\r
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\n" ); document.write( "\n" ); document.write( "at 5% level of significance, you would expect the z-score to be between -1.96 and 1.96 for 95% of the samples taken.\r
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\n" ); document.write( "\n" ); document.write( "this means the the sample mean would be between 19769 - 1.96 * 43.19 and 19769 + 1.96 * 43.19 for 95% of the sample taken.\r
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\n" ); document.write( "\n" ); document.write( "this would put the sample mean between 19684.35 and 19853.65 for 95% of the sample taken.\r
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\n" ); document.write( "\n" ); document.write( "this is well below the claimed maximum mean of 22450.\r
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\n" ); document.write( "\n" ); document.write( "the claim is therefore supported.\r
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\n" ); document.write( "\n" ); document.write( "it's not even close.\r
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\n" ); document.write( "\n" ); document.write( "each of the sample is assumed to have the same sample size of 150.\r
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