Answer: 1.509
Step-by-step explanation:
The formula of Margin of Error for (n<30):-
![E=t_{\alpha/2}\dfrac{\sigma}{\sqrt{n}}](https://tex.z-dn.net/?f=E%3Dt_%7B%5Calpha%2F2%7D%5Cdfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D)
Given : Sample size : n= 22
Level of confidence = 0.99
Significance level : ![\alpha=1-0.99=0.01](https://tex.z-dn.net/?f=%5Calpha%3D1-0.99%3D0.01)
Using the t-distribution table ,
Critical value : ![t_{n-1, \alpha/2}=t_{21,0.005}= 2.831](https://tex.z-dn.net/?f=t_%7Bn-1%2C%20%5Calpha%2F2%7D%3Dt_%7B21%2C0.005%7D%3D%202.831)
Standard deviation: ![\sigma=\text{ 2.5 dollars }](https://tex.z-dn.net/?f=%5Csigma%3D%5Ctext%7B%202.5%20dollars%20%7D)
Then, we have
![E=( 2.831)\dfrac{2.5}{\sqrt{22}}\approx1.509](https://tex.z-dn.net/?f=E%3D%28%202.831%29%5Cdfrac%7B2.5%7D%7B%5Csqrt%7B22%7D%7D%5Capprox1.509)
Hence, the margin of error for a 99% confidence interval for the population mean =1.509
Answer:
-2
Step-by-step explanation:
Answer:
46.46 gallons
Step-by-step explanation:
we know that
An airplane consumes 30.25 gallons of fuel in 2.8 hours of flying
so
using proportion
Find out how many gallons will it consume in 4.3 hours of flying
![\frac{30.25}{2.8}\ \frac{gal}{h}=\frac{x}{4.3}\ \frac{gal}{h}\\\\x=30.25*(4.3)/2.8\\\\x= 46.46\ gal](https://tex.z-dn.net/?f=%5Cfrac%7B30.25%7D%7B2.8%7D%5C%20%5Cfrac%7Bgal%7D%7Bh%7D%3D%5Cfrac%7Bx%7D%7B4.3%7D%5C%20%5Cfrac%7Bgal%7D%7Bh%7D%5C%5C%5C%5Cx%3D30.25%2A%284.3%29%2F2.8%5C%5C%5C%5Cx%3D%2046.46%5C%20gal)
Answer:
x=1
Step-by-step explanation:
To get the 7 away, we need to multiply it into the parentheses.
7*-10= -70
7*3=21
-70+21x= -49
Now we combine like terms and we move 70 over. Because we're moving it to the other side of the equation, it becomes positive.
21x= -49+70
-49+70 is the same as 70-49
70-49= 21
Now we put it together.
21x=21
To get the x by itself, we need to divide 21 on both sides.
21x/21= 21/21
21/21=1
x=1