Show all work to factor x4 – 17x2 + 16 completely.
2 answers:
Answer:
(x - 4)(x + 4)(x - 1)(x + 1)
Step-by-step explanation:
Given
- 17x² + 16
Use the substitution u = x², then
u² - 17u + 16
Consider the factors of the constant term (+ 16) which sum to give the coefficient of the u- term (- 17)
The factors are - 16 and - 1, then
u² - 17u + 16
= (u - 16)(u - 1) ← replace u by x²
= (x² - 16)(x² - 1) ← both factors are difference of squares
= (x - 4)(x + 4)(x - 1)(x + 1)
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<h3>Answer: Choice B</h3>
No, this is not a plausible value for the population mean, because 5 is not within the 95% confidence interval.
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Explanation:
The greek letter mu is the population mean. It has the symbol which looks like the letter 'u' but with a tail at the front or left side.
The question is asking if mu = 5 is plausible if the researcher found the 95% confidence interval to be 5.2 < mu < 7.8
We see that 5 is <u>not</u> in that interval. It's a bit to the left of 5.2
Since mu = 5 is not in the interval, it's not a plausible value for the population mean.
Have we ruled it out with 100% confidence? No. Such a thing is not possible. There's always room for (slight) error. The researcher would need to do a census to be fully confident; however, such practices are very time consuming and expensive. This is the main reason why statistics is important to try to estimate the population with a sample.