Find all the factors of 125
1 answer:
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Answer:
We conclude that the residents of Wilmington, Delaware, have higher income than the national average
Step-by-step explanation:
We are given the following in the question:
Population mean, μ = $44,500
Sample mean, = $52,500
Sample size, n = 16
Alpha, α = 0.05
Sample standard deviation, s = $9,500
a) First, we design the null and the alternate hypothesis
We use one-tailed(right) t test to perform this hypothesis.
c) Formula:
Putting all the values, we have
b) Rejection rule
If the calculated t-statistic is greater than the t-critical value, we fail to accept the null hypothesis and reject it.
Now,
Since,
We fail to accept the null hypothesis and reject it. We accept the alternate hypothesis. We conclude that the residents of Wilmington, Delaware, have higher income than the national average
Answer:
w= 9
Step-by-step explanation:
Square both sides:
-4w +61= (w -4)²
Expand:
-4w +61= w² -2(w)(4) +4²
-4w +61= w² -8w +16
Simplify:
w² -8w +16 +4w -61= 0
w² -4w -45= 0
Factorize:
(w -9)(w +5)= 0
w -9= 0 or w +5= 0
w= 9 or w= -5 (reject)
Note:
-5 is rejected since we are only taking the positive value of the square root here. If the negative square root is taken into consideration, then w= -5 would give us -9 on both sides of the equation.
<u>Why </u><u>do </u><u>we </u><u>use </u><u>negative </u><u>square </u><u>root?</u>
When solving an equation such as x²= 4,
we have to consider than squaring any number removes the negative sign i.e., the result of a squared number is always positive.
In the case of x²= 4, x can be 2 or -2. Thus, whenever we introduce a square root, a '±' must be used.
However, back to our question, we did not introduce the square root so we should not consider the negative square root value.