Assume that heights of students are normal distributed with mean 175 Cm and standard deviation 15 Cm. We select randomly a student. What is the probability that the height of the
selected student is not different from the mean value by more than two standard deviation ?
-0.9772
-0.0228
-The correct answer is not found
-0.9544

Planet earth has a mass of 5.9726x10²⁴ kg.then: 5.9726x10²⁴ kg=100% of the total earth mass.if the water´s mass=5x10-4 % of the total mass, we can solve this problem by the rule of three.5.9726x10²⁴ %*10⁻⁴ %x=(5.9726x10²³ kg)(5*10⁻⁴  %) / 100 %=2.9863x10¹⁹ kganswer:   the mass of the planet´s water would be   2.9863 x 10¹⁹ kg.