Answer:
Critical value: z = 1.28
The 80% confidence interval for the mean repair cost for the washers is between $46.487 and $82.033.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
![\alpha = \frac{1-0.80}{2} = 0.10](https://tex.z-dn.net/?f=%5Calpha%20%3D%20%5Cfrac%7B1-0.80%7D%7B2%7D%20%3D%200.10)
Now, we have to find z in the Ztable as such z has a pvalue of ![1-\alpha](https://tex.z-dn.net/?f=1-%5Calpha)
So it is z with a pvalue of 1-0.1 = 0.9, so z = 1.28
Now, find the margin of error M as such
![M = z*\frac{\sigma}{\sqrt{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%2A%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D)
In which
is the standard deviation of the population and n is the size of the sample.
So
![M = 1.28*\frac{27.77}{\sqrt{4}} = 17.773](https://tex.z-dn.net/?f=M%20%3D%201.28%2A%5Cfrac%7B27.77%7D%7B%5Csqrt%7B4%7D%7D%20%3D%2017.773)
The lower end of the interval is the mean subtracted by M. So 64.26 - 17.773 = $46.487.
The upper end of the interval is M added to the mean. So 64.26 + 17.773 = $82.033.
The 80% confidence interval for the mean repair cost for the washers is between $46.487 and $82.033.
Answer:
exact form: 13 over 6
decimal form: 2.16
mixed number form: 2/ 1 over 6
I’m pretty sure the answer is A
Answer:
To write as a scientific notation in this problem, just make something 0.0 x 10n
In this case, this is 8.9. Then, think about how many 10s have to be multiplied to make 8900.
It's three!
Move the decimal point left to 3 places to make 5.78. Then, n is the number of decimal places you moved:3
Same goes to the case 0.034. You need to make something 0.0 x 10n
Hence, move the decimal point right to 2 places to make 3.4. How many decimal places did you move?Two!
But because you went right to make it from 0.034 to 3.4, n becomes -2(the number got 100 times smaller).
Just don't forget to add that negative sign after you have solved a problem involving a number smaller than 1.
Step-by-step explanation:
Hope this helps you.
:)