Alexandra's bank statement shows a closing balance of $130.68. There are no outstanding checks or deposits. Her checkbook shows
2 answers:
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Answer:
a) Mean = 1030; Standard deviation = 12.38.
b) The county result is unusually high.
Step-by-step explanation:
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by
After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X. Subtracting 1 by the pvalue, we This p-value is the probability that the value of the measure is greater than X.
(a) Find the mean and standard deviation for the number of high school graduates in groups of 1210 Americans over the age of 25.
This first question is a binomial propability distribution.
We have a sample of 1210 Amricans, so .
The mean of the sample is 1030.
The probability of a success is .
The standard deviation of the sample is
(b) Is that county result of 1030 unusually high, or low, or neither?
The first step is find the zscore when .
Then we find the pvalue of this zscore.
If this pvalue is bigger than 0.95, the county result is unusually high.
If this pvalue is smaller than 0.05, the county result is unusually low.
Otherwise, it is neither.
The national mean is 82%. So,
has a pvalue of 0.9989.This means that the county result is unusually high.
Answer:
All three operations lead to polynomials.
See explanations below.
Step-by-step explanation:
Polynomial a =
Polynomial b =
Therefore:
a + b =
where we have combined all like terms. This is clearly another polynomial (of grade 2)
a - b (here we need to flip all signs inside the parenthesis when we remove this grouping symbol):
which is clearly another polynomial (but of grade 3)
a * b : (here we use distributive property to multiply each term of the first polynomial by each term of the second one, and then combine like terms)
which is indeed another polynomial (this time of grade 6)