Average Senior High School annual cost of tuition fee for all private schools last year was 46,300 a random sample of costs this year for 45 private schools indicated that the sample mean was 47,800 and a sample standard deviation was 5600 at the 0.10 level of significance, is there sufficient evidence to conclude that the cost has increased?
"\\mu = 46300 \\\\\n\nn = 45 \\\\\n\n\\bar{X} = 47800 \\\\\n\n\\sigma = 5600 \\\\\n\nz = \\frac{\\bar{X} - \\mu}{\\sigma \/ \\sqrt{n}} \\\\\n\nz = \\frac{47800 -46300}{5600 \/ \\sqrt{45}} \\\\\n\n= \\frac{1500}{834.82} \\\\\n\n= 1.79 \\\\\n\nZ_{\u03bb\/2} = Z_{0.10\/2} = Z_{0.05} = 1.645 \\\\\n\n1.79 > 1.645"
There is sufficient evidence to conclude that the cost has increased.
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