Name:__________________________________________ Block:_____ Date:______________
STUDY GUIDE
Study Guide: Skills and Stats Quarter 2
The Skills and Stats Test will include:



Measures of Dispersion (standard deviation and mean absolute deviation)
Z-Scores
Literal Equations
Standard Deviation: Square root of the averages of the sum of the deviations squared.
When should you use MAD?
Mean Absolute Deviation is the mean of the absolute values of the deviations. Use MAD when there is an outlier in
your data.
Standard Deviation Example:
Data set #1: 2.97 Data set #2: 6.16
What does a larger standard deviation mean?
Z-Scores
Z-Score: The number of standard deviations from the mean.
Standard Normal Distribution
with Z-Scores
Z-Score formula:
Practice:
1. Find the z-score corresponding to a raw score of 132 from a normal distribution with a mean of 100 and a
standard deviation of 15.
2.
Find the raw score if the z-score is 1.7, mean is 14, and standard deviation is 3.
3.
Find the raw score if the z-score is 2.4, mean is 300, and standard deviation is 20.
4.
If the raw score is 92, mean is 70, and the z-score is 2.75, what is the standard deviation?
5.
Literal Equations
A literal equation is an equation in which letters are used to replace the coefficients and constants of another equation.
Example: The equation 5(x + 3) = 20 can be written as the literal equation a(x + b) = c.
Practice: Solve each literal equation for the indicated variable.
1. ax – bx = c (solve for x)
2. ax = bx + c (solve for x)
2. 3x + 2y = 8 (solve for y)
4. A = bh (solve for h)
5.
6. 8x – 2y = 16 (solve for y)
P = 2l + 2w (solve for w)
1
2
7. 7x + 3y = 6 – 5x (solve for y)
8. xy – h = w (solve for y)
9. H = 2a + 7ad (solve for a)
10. 30 = 9x – 5y (solve for y)
11. x =
𝑎+𝑏+𝑐
𝑎𝑏
(solve for a)
13. S = πrl + πr2
12. y = x(
(solve for r)
𝑎𝑏
𝑎−𝑏
)
(solve for a)
14. 4(2x – y) = 6 (solve for y)
1
15. The formula for the area of a trapezoid is A = (b1 + b2)h. Which equation is NOT
2
equivalent to the fomula?
A. h =
2𝐴
𝑏1+ 𝑏2
B. b1 =
2𝐴
ℎ
− 𝑏2
C. b2 =
2𝐴
𝑏1
–h
D. b2 =
2𝐴
ℎ
- b1