4x-3=5x-21 what does x=

Kathy rode her bike 8 miles today. This was 1/4 of the miles she rode this month. How many miles m did Kathy ride her bike this

anastassius [24]

So basically it would be 8x4

4 0

4 years ago

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A doctor is measuring the average height of male students at a large college. The doctor measures the heights, in inches, of a s

denpristay [2]

Answer:

For this case the 95% confidence interval is given (63.5 , 74.4) and we want to conclude about the result. For this case we can say that the true mean of heights for male students would be between 63.5 and 74.4. And the best answer would be:

b. The doctor can be 95% confident that the mean height of male students at the college is between 63.5 inches and 74.4 inches.

Step-by-step explanation:

Notation

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the mean and the sample deviation we can use the following formulas:

$\bar X= \sum_{i=1}^n \frac{x_i}{n}$ (2)

$s=\sqrt{\frac{\sum_{i=1}^n (x_i-\bar X)}{n-1}}$ (3)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=40-1=39$

For this case the 95% confidence interval is given (63.5 , 74.4) and we want to conclude about the result. For this case we can say that the true mean of heights for male students would be between 63.5 and 74.4. And the best answer would be:

b. The doctor can be 95% confident that the mean height of male students at the college is between 63.5 inches and 74.4 inches.

3 0

4 years ago

Which point best represents pi? Explain your answer.

MaRussiya [10]

Answer:

A and A- minus that is my best time

5 0

3 years ago

the reflecting dish of a parabolic microphone has a cross-section in the shape of a parabola.the microphone itself is placed on

Alchen [17]

Well we could look at it like this. we can make a generic equation for this by saying that the vertex lies at (0,0). we know that it is 24 inches wide. this means that on either side of the vertex is 12 inches. since it is 4 inches deep, we know that these points at x = -12, 12 have a y = 4. to make the equation we look at the vertex form of parabolas:
y=a(x−h)^2+k

we can plug in the point (-12,4) and the vertex
4 = a (-12 + 0)^2 + 0
4 = a (144)
a = 1/36

the vertex is
(h,k) or (0,0)

and the focus point :
(h,k+1/4a) or (0,0 + 1/(4/32)
(0, 1/(1/9))
(0, 9)

this would mean that the focus point is 9 inches above the vertex.

6 0

3 years ago

What is the constant of proportionality of y=25x?

garik1379 [7]

Answer:

25x is the constant

Step-by-step explanation

This is right becuase the x is your constant which is 25

4 0

3 years ago