Answer:
Where
and
Then we have:
With the following parameters:


Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the number of cars running a red light of a population, and for this case we know the distribution for X is given by:
Where
and
Since the distribution for X is normal then we know that the distribution for the sample mean
is given by:
With the following parameters:


For this case, we observe that the triangles are similar.
We observe that the triagnules have three equal angles.
Therefore, to find the value of x we can use the following relationship:

Clearing x we have:
Answer:
The value of x is given by:
x = 6.25
Answer:
x = 6
Step-by-step explanation:
-2 + x = 4
x = 4 + 2
x = 6
Thank you :-)