What's 67% as a decimal?
2 answers:
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A ) ![\sqrt[4]{ x^{3} } = x^{3/4}](https://tex.z-dn.net/?f=%20%5Csqrt%5B4%5D%7B%20x%5E%7B3%7D%20%7D%20%3D%20x%5E%7B3%2F4%7D%20)
B )
C )![\sqrt[10]{ x^{5} * x^{4}* x^{2} } = \sqrt[10]{ x^{11} }= x^{11/10}](https://tex.z-dn.net/?f=%20%5Csqrt%5B10%5D%7B%20x%5E%7B5%7D%20%2A%20x%5E%7B4%7D%2A%20x%5E%7B2%7D%20%20%7D%20%3D%20%5Csqrt%5B10%5D%7B%20x%5E%7B11%7D%20%7D%3D%20x%5E%7B11%2F10%7D%20%20)
D )
Therefore: B = D
B )
C )
D )
Therefore: B = D
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:
Now, we have to find z in the Ztable as such z has a pvalue of
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
In which is the standard deviation of the population and n is the size of the sample.
So
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.