document.write( "Question 1175015: 4. You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately
\n" ); document.write( "σ=36.7. You would like to be 90% confident that your esimate is within 0.1 of the true population mean. How large of a sample size is required? n =
\n" ); document.write( "Do not round mid-calculation. However, use a critical value accurate to three decimal places — this is important for the system to be able to give hints for incorrect answers\r
\n" ); document.write( "\n" ); document.write( "5. In a survey, 12 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $42 and standard deviation of $13. Construct a confidence interval at a 95% confidence level.Give your answers to one decimal place. \n" ); document.write( "
Algebra.Com's Answer #800618 by ewatrrr(24785)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Hi\r\n" );
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document.write( "4.  population standard deviation  σ=36.7\r\n" );
document.write( " 90% confident level\r\n" );
document.write( "ME =\"+z%2Asigma%2Fsqrt%28n%29\"  0r n = (t*sigma/ME)^2\r\n" );
document.write( " n = [(1.96(36.7)/(.1)]^2 = \r\n" );
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document.write( "5.      x̄ = 42    sd = 13     95% confidence level\r\n" );
document.write( "ME =\"+t%2Asigma%2Fsqrt%28n%29\"\r\n" );
document.write( "ME = 2.201(13)/√12           |df = 11  (n-1)\r\n" );
document.write( "42 - ME < \"mu\" < 42 + ME\r\n" );
document.write( "Wish You the Best in your Studies.\r\n" );
document.write( "Confidence Level	80%	90%	95%	98%	99%\r\n" );
document.write( "Two-sided test p-values	0.2	0.1	0.05	0.02	0.01\r\n" );
document.write( "One-sided test p-values	0.1	0.05	0.025	0.01	0.005\r\n" );
document.write( "Degrees of Freedom (df=n-1)					\r\n" );
document.write( "               1	3.078	6.314	12.71	31.82	63.66\r\n" );
document.write( "               2	1.886	2.92	4.303	6.965	9.925\r\n" );
document.write( "               3	1.638	2.353	3.182	4.541	5.841\r\n" );
document.write( "               4	1.533	2.132	2.776	3.747	4.604\r\n" );
document.write( "               5	1.476	2.015	2.571	3.365	4.032\r\n" );
document.write( "               6	1.44	1.943	2.447	3.143	3.707\r\n" );
document.write( "               7	1.415	1.895	2.365	2.998	3.499\r\n" );
document.write( "               8	1.397	1.86	2.306	2.896	3.355\r\n" );
document.write( "               9	1.383	1.833	2.262	2.821	3.25\r\n" );
document.write( "              10	1.372	1.812	2.228	2.764	3.169\r\n" );
document.write( "              11	1.362	1.796	2.201	2.718	3.106\r\n" );
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