<span>9a + -3(2a + -4) = 15
Reorder the terms:
9a + -3(-4 + 2a) = 15
9a + (-4 * -3 + 2a * -3) = 15
9a + (12 + -6a) = 15
Reorder the terms:
12 + 9a + -6a = 15
Combine like terms: 9a + -6a = 3a
12 + 3a = 15
Solving
12 + 3a = 15
Solving for variable 'a'.
Move all terms containing a to the left, all other terms to the right.
Add '-12' to each side of the equation.
12 + -12 + 3a = 15 + -12
Combine like terms: 12 + -12 = 0
0 + 3a = 15 + -12
3a = 15 + -12
Combine like terms: 15 + -12 = 3
3a = 3
Divide each side by '3'.
a = 1
Simplifying
a = 1</span>
Answer:
The Correct option is - d. all of the above.
Step-by-step explanation:
To find - In assessing the validity of any test of hypotheses, it is good practice to
a. examine the probability model that serves as a basis for the test by using exploratory data analysis on the data.
b. determine exactly how the study was conducted.
c. determine what assumptions the researchers made.
d. all of the above.
Proof -
All the Given options are correct to study the validity of a hypothesis test.
So,
The Correct option is - d. all of the above.
Answer:
The 95% confidence interval for the true mean speed of thunderstorms is [10.712, 13.688].
Step-by-step explanation:
Given information:
Sample size = 10
Sample mean = 12.2 mph
Standard deviation = 2.4
Confidence interval = 95%
At confidence interval 95% then z-score is 1.96.
The 95% confidence interval for the true mean speed of thunderstorms is

Where,
is sample mean, z* is z score at 95% confidence interval, s is standard deviation of sample and n is sample size.



![CI=[12.2-1.488, 12.2+1.488]](https://tex.z-dn.net/?f=CI%3D%5B12.2-1.488%2C%2012.2%2B1.488%5D)
![CI=[10.712, 13.688]](https://tex.z-dn.net/?f=CI%3D%5B10.712%2C%2013.688%5D)
Therefore the 95% confidence interval for the true mean speed of thunderstorms is [10.712, 13.688].
Answer:
4 1/6
Step-by-step explanation:
15 3/4 ÷ 2 5/8 × 5 5/6 ÷ 8 2/5
assuming this order of operations:
(15 3/4 ÷ 2 5/8) × (5 5/6 ÷ 8 2/5)
63/4 x 8/21 = 505/84 = 6
35/6 x 5/42 = 175/252
6 x 175/252 = 1050/252 = 4 42/252 = 4 1/6