Y=-3x+27 6y-x+9=0 substitution
1 answer:
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Answer:
d. t distribution with df = 80
Step-by-step explanation:
Assuming this problem:
Consider independent simple random samples that are taken to test the difference between the means of two populations. The variances of the populations are unknown, but are assumed to be equal. The sample sizes of each population are n1 = 37 and n2 = 45. The appropriate distribution to use is the:
a. t distribution with df = 82.
b. t distribution with df = 81.
c. t distribution with df = 41.
d. t distribution with df = 80
Solution to the problem
When we have two independent samples from two normal distributions with equal variances we are assuming that
And the statistic is given by this formula:
Where t follows a t distribution with degrees of freedom and the pooled variance
is given by this formula:
This last one is an unbiased estimator of the common variance
So on this case the degrees of freedom are given by:
And the best answer is:
d. t distribution with df = 80
Answer:
A quadratic function.
Step-by-step explanation:
If you plot the points given in the table, you obtain the graph shown in the figure attached.
As you can see, it is a parabola, therefore, the function that best models the data is a quadratic function.
By definition, the parent function of a quadratic function is:
You can compress or stretch it in the y-direction by multiplying the function by a constant :
If , then the function is compressed.
If , then the function is stretched.
You can find the constant of the function asked as following:
- Substitute x=1 into the parent function to obtain the y-coordinate:
Then the point is (1,1)
- As you can see, with x=1 you obtain y=1 in the parent function, and in the function given in the table when x=1, y=2.5, therefore, the function is multiplied by 2.5. Therefore the constant is:
Then the function is:
