The Statistical Abstract of the United States published by the U.S. Census Bureau reports that the average annual consumption of
1 answer:
Answer:
a)
b)
c)
d)
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 heights of a population, and for this case we know the distribution for X is given by:
Where and
We select a random sample of n=36. And from the central limit theorem we know that the distribution for the sample is given by:
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:
Part b
For this case we want this probability:
And we can find this probability on this way:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.
Part c
If we apply this formula to our probability we got this:
Part d
For this case we want this probability:
And we can find this probability on this way:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.
You might be interested in
Answer:
54.5
Step-by-step explanation:
divide it to one rectangle and two different triangles.
Rectangles area: (8+3)*4 = 44
triangle top: 4*3/2 = 6
triangle bottom: 3*3/2= 4.5
sum the all up: 44+6+4.5 = 54.5
don't know how to do it with π though if that's obligatory
To factor both numerator and denominator in this rational expression we are going to substitute 
with 
; so 
and 
. This way we can rewrite the expression as follows:
Now we have two much easier to factor expressions of the form
. For the numerator we need to find two numbers whose product is 
(30) and its sum 
(-11); those numbers are -5 and -6. 
and 
.
Similarly, for the denominator those numbers are -2 and -5.
and 
. Now we can factor both numerator and denominator:
Notice that we have
in both numerator and denominator, so we can cancel those out:
But remember than
, so lets replace that to get back to our original variable:
Last but not least, the denominator of rational expression can't be zero, so the only restriction in the variable is
Now we have two much easier to factor expressions of the form
Similarly, for the denominator those numbers are -2 and -5.
Notice that we have
But remember than
Last but not least, the denominator of rational expression can't be zero, so the only restriction in the variable is