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A survey was conducted that asked 1003 people how many books they had read in the past year. Results indicated that x overbar eq

Sergio [31]

Answer:

The 99% confidence interval would be given (11.448;14.152).

Step-by-step explanation:

1) Important concepts and notation

A confidence interval for a mean "gives us a range of plausible values for the population mean. If a confidence interval does not include a particular value, we can say that it is not likely that the particular value is the true population mean"

$s=16.6$ represent the sample deviation

$\bar X=12.8$ represent the sample mean

n =1003 is the sample size selected

Confidence =99% or 0.99

$\alpha=1-0.99=0.01$ represent the significance level.

2) Solution to the problem

The confidence interval for the mean would be given by this formula

$\bar X \pm z_{\alpha/2} \frac{s}{\sqrt{n}}$

We can use a z quantile instead of t since the sample size is large enough.

For the 99% confidence interval the value of $\alpha=1-0.99=0.01$ and $\alpha/2=0.005$ , with that value we can find the quantile required for the interval in the normal standard distribution.

$z_{\alpha/2}=2.58$

And replacing into the confidence interval formula we got:

$12.8 - 2.58 \frac{16.6}{\sqrt{1003}}=11.448$

$12.8 + 2.58 \frac{16.6}{\sqrt{1003}} =14.152$

And the 99% confidence interval would be given (11.448;14.152).

We are confident that about 11 to 14 are the number of books that the people had read on the last year on average, at 1% of significance.

3 0

4 years ago

6. what is the parimeter of triangle ABC 8. What is the value of x

nalin [4]

Answer:

Perimeter = 20 units

x = 120°

Step-by-step explanation:

We are given a triangle ABC with known side lengths for all three sides and an inscribed circle.

We are to find the perimeter of triangle ABC and the value of x.

Perimeter of triangle ABC = 2 + 2 + 5 + 5 + 3 + 3 = 20 units

The kite shape at the end is a quadrilateral which has a sum of angles of 360 degrees.

Two out of four angles are right angles and one is 60 so we can find the value of x.

x = 360 - (90 + 90 + 60) = 120°

7 0

3 years ago

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What is the solution set of (3x - 1)2 = 5?

Virty [35]

The answer to (3x-1)2=5 is x= 7/6

8 0

3 years ago

The outside temperature can be estimated based on how fast crickets chirp. At 104 chirps per minute, the temperature is 63 degre

Rasek [7]

Answer:

For 124 chirps per minute the temperature is 68 ºF.

For 68 chirps per minute the temperature is 54 ºF.

Step-by-step explanation:

Linear functions are those whose graph is a straight line. A linear function has the following form

$f(x)=b+mx$

b is the constant term or the y intercept. It is the value of the dependent variable when x = 0.

m is the coefficient of the independent variable. It is also known as the slope and gives the rate of change of the dependent variable.

We know that

At 104 chirps per minute, the temperature is 63 ºF.

At 176 chirps per minute, the temperature is 81 ºF.

This information can be converted to Cartesian coordinates (x, y). Where x = the number of chirps per minute and y = the temperature in ºF.

To find a linear function that let us find the outside temperature from how fast crickets chirp we must:

Find the slope:

$m=\frac{y_2-y_1}{x_2-x_1}=\frac{81-63}{176-104}=\frac{1}{4}$

Find the equation:

$81=\frac{1}{4}\cdot 104+b$

Solving for b

$b=81-\frac{1}{4} (176)=37$

Therefore, the linear function is

$y=\frac{1}{4} \cdot x+37$

Now, using this linear function we can know the temperature when we know the chirps per minute:

For 124 chirps per minute the temperature is:

$y=\frac{1}{4} \cdot (124)+37=68$

For 68 chirps per minute the temperature is:

$y=\frac{1}{4} \cdot (68)+37=54$

6 0

3 years ago

Luke earned a salary of 48,048 last year. how much did he earn per month?

viktelen [127]

$4004 just take 48048 and divide that by 12 to get your answer

5 0

3 years ago

Read 2 more answers

Please help! due soon!​

Please help! due soon!