Answer:
x = 48/7
Step-by-step explanation:
There's two good ways to do this problem.
Option 1:
Translate "x varies directly as y" into the equation y=kx
Then you have to find k. After you "reset" your y=kx equation, fill in k and then solve for x. See image.
Option 2:
Translate "varies directly" into a proportion, which is two fractions equal to each other:
x/y = x/y
Fill in the three numbers given and cross multiply and solve to find the fourth number. See image.
Answer:
a)
And we can find this probability with this difference:
And using the norma standard distribution or excel we got:
b)
And using the complement rule we got:
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".
Part a
Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability with this difference:
And using the norma standard distribution or excel we got:
Part b
For this case we want this probability:
And we can use the z score and we got:
And using the complement rule we got: