Four lines are drawn on a coordinate plane to form trapezoid WXYZ. Which statements are true about the lines? Select all that ap
ply. Line WZ has the same slope as line XY. Line YX has a greater slope than line ZY.Line XW has a lesser slope than line YZ.Line ZW has the same y-intercept as line WZ. Line XY has a greater y-intercept than line XW
2 answers:
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Answer:
If we compare the the p value with the significance level provided , we see that
, so then we can reject the null hypothesis. and there is a significant increase in the miles per gallon from 2017 to 2019 at 10% of significance.
Step-by-step explanation:
Previous concepts
A paired t-test is used to compare two population means where you have two samples in which observations in one sample can be paired with observations in the other sample. For example if we have Before-and-after observations (This problem) we can use it.
Let put some notation :
x=test value 2017 , y = test value 2019
x: 28.7 32.1 29.6 30.5 31.9 30.9 32.3 33.1 29.6 30.8 31.1 31.6
y: 31.1 32.4 31.3 33.5 31.7 32.0 31.8 29.9 31.0 32.8 32.7 33.8
Solution to the problem
The system of hypothesis for this case are:
Null hypothesis:
Alternative hypothesis:
Because if we have an improvement we expect that the values for 2019 would be higher compared with the values for 2017
The first step is calculate the difference and we obtain this:
d: 2.4, 0.3, 1.7,3,-0.2, 1.1, -0.5, -3.2, 1.4, 2, 1.6, 2.2
The second step is calculate the mean difference
The third step would be calculate the standard deviation for the differences, and we got:
We assume that the true difference follows a normal distribution. The 4th step is calculate the statistic given by :
The next step is calculate the degrees of freedom given by:
Now we can calculate the p value, since we have a right tailed test the p value is given by:
If we compare the the p value with the significance level provided , we see that
, so then we can reject the null hypothesis. and there is a significant increase in the miles per gallon from 2017 to 2019 at 10% of significance.
Answer:
Step-by-step explanation:
Part A:
To complete the square, we will do the first few steps all at once, since they are necessary but not complicated to follow all at once. Set the function equal to 0 first, then move the constant over to the other side:
The most important rule for completing the square is that the leading coefficient (the number on the t-squared term) is a positive 1. Ours is, but if it wasn't it would need to be factored out.
Next, take half the linear term, square it, and add it to both sides. Our linear term is 6. Half of 6 is 3, and 3 squared is 9, so we add 9 to both sides:
On the right is simple addition, but on the left side, during this process we created a perfect square binomial that will reflect the h coordinate of the vertex. We will state that binomial and do the addition on the right both at the same time:
If you FOIL out the (t + 3)(t + 3) you will get back the polynomial
Now we can move the constant back over and set the polynomial back to equal f(t):
From this we determine the vertex to sit at (-3, -38)
Part B:
Because this is a positive parabola that opens upwards, the function will have a minimum value (if it was negative and opened upside down, it would have a minimum value). In other words, you know the vertex is a minimum because this is a positive parabola that opens upwards.
Part C:
The axis of symmetry is the line that cuts the parabola in half, creating 2 identical, mirror images. Because this parabola opens upwards, a vertical line is required to cut it into 2 identical halves. The vertical line has an equation " x = ". In the case of a positive parabola that opens upwards, the line of symmetry, what x = , will ALWAYS be the number that is inside the parenthesis with the x. Since the standard vertex form is
our vertex can be rewritten as (t - (-3)). Therefore, our axis of symmetry is
x = -3