Answer: 5.37
Step-by-step explanation:
Let x = ACT scores.
Given: ACT scores have a mean of 20.8 and 9 percent of the scores are above 28. The scores have a distribution that is approximately normal.
i.e. P(X>28)=0.09 (i)
Now,
![P(X>28)=P(\dfrac{X-\mu}{\sigma}>\dfrac{28-20.8}{\sigma})\\\\= P(z>\dfrac{7.2}{\sigma})\ \ \ \ [z=\dfrac{X-\mu}{\sigma}]](https://tex.z-dn.net/?f=P%28X%3E28%29%3DP%28%5Cdfrac%7BX-%5Cmu%7D%7B%5Csigma%7D%3E%5Cdfrac%7B28-20.8%7D%7B%5Csigma%7D%29%5C%5C%5C%5C%3D%20P%28z%3E%5Cdfrac%7B7.2%7D%7B%5Csigma%7D%29%5C%20%5C%20%5C%20%5C%20%5Bz%3D%5Cdfrac%7BX-%5Cmu%7D%7B%5Csigma%7D%5D)
(ii)
One -tailed z value for p-value of 0.09 =1.3408 [By z-table]
From (i) and (ii)
Hence, the standard deviation = 5.37
Multiply the first equation by 2 to then use elimination by adding the 2 equations.
So, 14x-2y=14
+. x+2y=6
Equals 15x=20 so x=20/15=4/3
Plug in to first equation to get y
7(4/3)-y=7
28/3-y=7
28/3-y=21/3
So y=7/3
Plug both x and y into second equation to check
4/3+2(7/3)=
4/3+14/3=18/3=6 it works
So x=4/3, y=7/3
Hope this helps! Have a blessed day!
Answer:
View Image
Step-by-step explanation:
View Image
Answer:
The correct answer is that all trapezoids are quadrilaterals. ... Trapezoids are four-sided polygons, so they are all quadrilaterals.
Step-by-step explanation:
hope it helped ( ◜‿◝ )♡
A. = 7/8
b. = 7/4 = 1 3/4
c. = 7/4 = 1 3/4
d. = 7/4 = 1 3/4
= b,c,d
