"n=5000 \\\\\n\n\u03bc=8.4 \\\\\n\n\u03c3 = 1.7 \\\\\n\n(a) \\; P(X>13.5) = P(\\frac{X-\u03bc}{\u03c3}> \\frac{13.5-8.4}{1.7}) \\\\\n\n=P(Z>3) \\\\\n\n= 1 -P(Z<3) \\\\\n\n= 1 -0.9987 \\\\\n\n= 0.0013 \\\\\n\n(b) \\; P(X\u22645) = P(\\frac{X-\u03bc}{\u03c3} \u2264 \\frac{5-8.4}{1.7}) \\\\\n\n= P(Z \u2264 -2) \\\\\n\n= 1 -P(Z\u22642) \\\\\n\n= 1 -0.4772 \\\\\n\n= 0.0228"
(c) Chebyshev’s Theorem can be applied to both left skewed and right skewed distributions.
It states that Percentage of values that lies within k standard deviations from mean = 1 - (1/k²)
"0.68 = 1- \\frac{1}{k^2} \\\\\n\n\\frac{1}{k^2} = 1- 0.68 =0.32 \\\\\n\nk = \\sqrt{\\frac{1}{0.32}} = 1.768 \\\\\n\nRange = 8.4- 1.768 \\times 1.7 = 5.3944 \\\\\n\nRange = 8.4+ 1.768 \\times 1.7=11.4056 \\\\\n\n(5.3944, 11.4056) \\\\\n\n(d) \\; P(6.7<X<11.8) = P(\\frac{6.7-8.4}{1.7} < \\frac{X-\u03bc}{\u03c3} < \\frac{11.8-8.4}{1.7}) \\\\\n\n= P(-1 <Z < 2) \\\\\n\n= P(Z<2) -P(Z <-1) \\\\\n\n= 0.9772 -0.1586 \\\\\n\n= 0.8186"
(e) Similar to the c part:
"Range = 8.4 -k \\times 1.7 = 5.34 \\\\\n\nRange = 8.4 +k \\times 1.7 = 11.46 \\\\\n\nk = 1.8 \\\\\n\nP = 1- \\frac{1}{k^2} \\\\\n\n= 1 -\\frac{1}{(1.8)^2} \\\\\n\n= 0.69"
Answer: 69 %
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