This question aims to find the probability of a normally distributed random variable
The normal distribution, also known as the Gaussian distribution or the z-distribution, has a mean of zero and a standard deviation of one. Data in a normal distribution is symmetrically distributed and has no skew. The data takes the shape of a bell when plotted on a graph, with most values grouping around a central region and scattering off as they move away from the center.
The two characteristics such as mean and standard deviation define the graph of the normal distribution. The mean/average is the maximum of the graph, whereas the standard deviation measures the amount of spread away from the mean.
Expert Answer
Let
Since,
So, by inverse use of the
Therefore, Var (X)
Example 1
Consider
Solution
Here,
Therefore,
Now,
Also,

Area under the normal curve between
Example 2
The time between battery charges for some specific types of computers is normally distributed, with a mean of
Solution
Here,
To find:
Now,
Example 3
A normal distribution model with a mean of
Solution
Given,
To find:
Now,
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