84 students who took the achievement test last Oct. 2020 If the mean is 88, s = 2.50. how many students scored above the mean?
"P(X>88) = 1-P(X<88) \\\\\n= 1 -P(Z< \\frac{88-88}{2.5}) \\\\\n= 1 - P(Z<0) \\\\\n= 1 -0.5 \\\\\n= 0.5 \\\\\nn=84 \\\\\nExpected = np = 84 \\times 0.5 = 42"
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