Question

4. Monthly consumption of electricity X (in KWH, in a winter month) by the households in a county has a normal distribution with mean 875 KWH and standard deviation 155 KWH. What proportions of house- holds consumes less than 1000 KwH? P(xc1000)sp (Zc1000-175 he monthly cell phone minutes used by an individual in a city has normal distribution with mean 2700 minutes and standard deviation 5. T

Answer 1

Given data is monthly consumption of electricity x in KWH, in a winter month The normal distribution with the mean 875 KWH The standard deviation 155 KWH Therefore The properties of house-holds consume and less than 1000 KWH is P (x < 1000) = P (z < 1000 - 875/155) = p (z < 0.81) p (x < 1000) = 0.7910 (5) The monthly minutes used individual in a city as the normal distribution with mean 2700 min standard deviation 325 min Therefore The properties of calls would list more than 3000 minutes p (x > 3000) = p (z > 3000 - 2700/325) = p (z > 0.92) = 1 - 0.8212 p (x > 3000) = 0.1780