On the planet of Mercury, 4-year-olds average 2.8 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
Normal distribution: A continuous random variable x is said to follow normal distribution with parameter and , if it's pdf is,
Here we calculate the probability by using z-score,
The formula is,
were,
x ~ normal distribution,
: Population mean.
: Population standard deviation.
Given,
Population mean =
Population standard deviation = = 2.5
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