(program in Matlab) calculates the probability
of given values on
a standard normal
distribution curve (Gauss’
You have to enter the mean,
the standard deviation
and the value of interest. No special toolboxes or
strange instructions are used.
shaded area represents the probability of ‘x’,
and its frequency is ‘y’.
normal probability is approximated using the following formula:
= 1 – r(a1t + a2t2 + a3t3)
= 1/(1 + 0.33267x)
the Matlab code to accomplish the task,
Clears screen and deletes all the variables in the workspace
Asks the user for input
m = input('Mean:
Calculates the frequency (y coordinate)
abs((y - m)/s);
str = ['Frequency:
z = y;
Approximates probability (area under curve)
y = 1/(1
t = 1 -
r*(a1*y + a2*y^2 + a3*y^3);
if z <
t = 1 - t;
str = ['Probability:
mean instructions per millisecond (IPMS) of a certain type of
The standard deviation is 15 IPMS. If the IPMS are normally
is the probability that a computer executes between 150 and 180
instructions per millisecond?
Run the Matlab code above and enter...
x = 180
handy Matlab response is
we need to know the probability of an execution of 130 and 150
milliseconds for the same type of modern computers?
worry, Matlab is here...
x = 130
the handy response is
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