Answer:
And if we solve for a we got
So the value of height that separates the bottom 20% of data from the top 80% is 23.432.
Step-by-step explanation:
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
For this part we want to find a value a, such that we satisfy this condition:
(a)
(b)
As we can see on the figure attached the z value that satisfy the condition with 0.20 of the area on the left and 0.80 of the area on the right it's z=-0.842
If we use condition (b) from previous we have this:
But we know which value of z satisfy the previous equation so then we can do this:
And if we solve for a we got
So the value of height that separates the bottom 20% of data from the top 80% is 23.432.
It’s C. ( 3 . -5 ), because the you want to look at where the two lines intersect. So you want to always look at the X - Axis first. And that’s on the 3. Now you want to look at the Y - Axis. And that’s on - 5. So you answer will be C. ( 3 . -5 )
Question 2 is 19.4 I hope I helped!
4:1.
56,000÷2 = 28,000
14,000÷2 = 7,000
28,000/7,000 = 28/7
28 ÷ 7 = 4
---- -----
7 ÷7 = 1
4:1
Hope this helps!
1/4 saved, 3/4
1/3 of the rest (4/4-1/4=3/4, 3/4=rest)
1/3 of 3/4=3/12=1/4
saved=1/4
spent on t-shirt=1/4
CD=?
1/4+1/4+?=4/4
2/4+?=4/4
minus 2/4
?=2/4
?=1/2
spent 1/2 on CDs