On the planet of Mercury, 4-year-olds average 3.1 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.3 hours and the amount of time spent alone is normally distributed. We randomly survey one Mercurian 4-year-old living in a rural area. We are interested in the amount of time X the child spends alone per day. (Source: San Jose Mercury News) Round all answers to 4 decimal places where possible. a. What is the distribution of X? X ~ N b. Find the probability that the child spends less than 3.4 hours per day unsupervised. c. What percent of the children spend over 4.9 hours per day unsupervised. % (Round to 2 decimal places) d. 86% of all children spend at least how many hours per day unsupervised? hours
Unitary Method
The word “unitary” comes from the word “unit”, which means a single and complete entity. In this method, we find the value of a unit product from the given number of products, and then we solve for the other number of products.
Speed, Time, and Distance
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Profit and Loss
The amount earned or lost on the sale of one or more items is referred to as the profit or loss on that item.
Units and Measurements
Measurements and comparisons are the foundation of science and engineering. We, therefore, need rules that tell us how things are measured and compared. For these measurements and comparisons, we perform certain experiments, and we will need the experiments to set up the devices.
On the planet of Mercury, 4-year-olds average 3.1 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.3 hours and the amount of time spent alone is
a. What is the distribution of X? X ~ N
b. Find the probability that the child spends less than 3.4 hours per day unsupervised.
c. What percent of the children spend over 4.9 hours per day unsupervised. % (Round to 2 decimal places)
d. 86% of all children spend at least how many hours per day unsupervised? hours
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