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3 years ago

(05.03 MC)

1 answer:

7 0

A) The rate of change is -40 songs each week, that is because the amount of songs left to be downloaded decrease by 40 each week

B) lets use 2 points of the graph p1(0, 200), p2(1, 160)
calculate the slope:
m = (y2- y1)/(x2 - x1) = (160 - 200)/(1 - 0)
m = -40
now use line equation in form point-slope:
y - y1 = m(x - x1)
y - 200 = -40(x - 0)
y = -40x + 200

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Please help guys need help

dmitriy555 [2]

Answer:

A) slope = 20.

B) The slope of 20 dollars per hour means that for every hour, the price of the service call increases by 20 dollars (or you could say the price of the service call is 20 dollars every hour, both work.)

Step-by-step explanation:

Recall that slope is y2 - y1 / x2 - x1.

Excellent. We are provided with two points: (1, 60) and (3, 100). Let’s enter this into our formula.

Slope = (100 - 60) / (3 - 1) = 40 / 2 = 20.

Now, to determine what the slope means, we can look at the axis titles on the graph. The x axis title is hours, or time in hours. The y axis title is price of the service call in dollars. Therefore, the slope is price (in dollars) per time (in hours).

This can be restated as: The slope of 20 dollars per hour means that for every hour, the price of the service call increases by 20 dollars (or you could say the price of the service call is 20 dollars every hour, both work.)

Hope this helps!

7 0

3 years ago

Help with 9 and 10 please?

JulsSmile [24]

9. Let x equal the number

Two less than a number is

x - 2

Is more than 15 is

> 15

Put them together for

x-2 > 15

Now solve

x-2 > 15
x > 17

10. Let x equal a number

Seven more than a number is

x+ 7

Is less than or equal to 27 is

<= 27

Put them together for

x + 7 <= 27

Now solve

x+ 7 <= 27
x <= 20

3 0

3 years ago

Ryan has 8 kittens. Two are white. Julie has 4 kittens. The fraction of the kittens that are not whites the same for Ryan and Ju

Studentka2010 [4]

Answer:

2/4

Step-by-step explanation:

7 0

3 years ago

Read 2 more answers

Good morning please help me im in desperate need thxs

Marat540 [252]

Answer:

Should be 4/7

Hope it helps have a good day!

7 0

3 years ago

An article in The Engineer (Redesign for Suspect Wiring," June 1990) reported the results of an investigation into wiring errors

GarryVolchara [31]

Answer:

a) The 99% confidence interval on the proportion of aircraft that have such wiring errors is (0.0005, 0.0095).

b) A sample of 408 is required.

c) A sample of 20465 is required.

Step-by-step explanation:

Question a:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

Of 1600 randomly selected aircraft, eight were found to have wiring errors that could display incorrect information to the flight crew.

This means that $n = 1600, \pi = \frac{8}{1600} = 0.005$

99% confidence level

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $Z = 2.575$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.005 - 2.575\sqrt{\frac{0.005*0.995}{1600}} = 0.0005$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.005 + 2.575\sqrt{\frac{0.005*0.995}{1600}} = 0.0095$

The 99% confidence interval on the proportion of aircraft that have such wiring errors is (0.0005, 0.0095).

b. Suppose we use the information in this example to provide a preliminary estimate of p. How large a sample would be required to produce an estimate of p that we are 99% confident differs from the true value by at most 0.009?

The margin of error is of:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

A sample of n is required, and n is found for M = 0.009. So

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.009 = 2.575\sqrt{\frac{0.005*0.995}{n}}$

$0.009\sqrt{n} = 2.575\sqrt{0.005*0.995}$

$\sqrt{n} = \frac{2.575\sqrt{0.005*0.995}}{0.009}$

$(\sqrt{n})^2 = (\frac{2.575\sqrt{0.005*0.995}}{0.009})^2$

$n = 407.3$

Rounding up:

A sample of 408 is required.

c. Suppose we did not have a preliminary estimate of p. How large a sample would be required if we wanted to be at least 99% confident that the sample proportion differs from the true proportion by at most 0.009 regardless of the true value of p?

Since we have no estimate, we use $\pi = 0.5$