Answer:
59 to 66
Step-by-step explanation:
Mean test scores = u = 74.2
Standard Deviation =
= 9.6
According to the given data, following is the range of grades:
Grade A: 85% to 100%
Grade B: 55% to 85%
Grade C: 19% to 55%
Grade D: 6% to 19%
Grade F: 0% to 6%
So, the grade D will be given to the students from 6% to 19% scores. We can convert these percentages to numerical limits using the z scores. First we need to to identify the corresponding z scores of these limits.
6% to 19% in decimal form would be 0.06 to 0.19. Corresponding z score for 0.06 is -1.56 and that for 0.19 is -0.88 (From the z table)
The formula for z score is:
![z=\frac{x-u}{\sigma}](https://tex.z-dn.net/?f=z%3D%5Cfrac%7Bx-u%7D%7B%5Csigma%7D)
For z = -1.56, we get:
![-1.56=\frac{x-74.2}{9.6}\\\\ x = 59](https://tex.z-dn.net/?f=-1.56%3D%5Cfrac%7Bx-74.2%7D%7B9.6%7D%5C%5C%5C%5C%20x%20%3D%2059)
For z = -0.88, we get:
![-0.88=\frac{x-74.2}{9.6}\\\\ x = 66](https://tex.z-dn.net/?f=-0.88%3D%5Cfrac%7Bx-74.2%7D%7B9.6%7D%5C%5C%5C%5C%20x%20%3D%2066)
Therefore, a numerical limits for a D grade would be from 59 to 66 (rounded to nearest whole numbers)
C.!!!!!!!!!!!!!!!!!!!!!!!
Lol i learned that today sorry i didn't get it either
The second piece would be 28 cm.
You could solve this by subtracting 7 from 63 first. Next you divide it by two one piece is 35 and the other 28.
(Have a nice day :) )
3.85 You take the 46.2 and divide the 12 gallons of gas.