Please help! I’m not good at this

Eight balls numbered from 1 to 8 are placed in an urn. One ball is selected at random. Find the probability that it is

elena-14-01-66 [18.8K]

Answer:

$\frac{7}{8}$

Step-by-step explanation:

6 0

4 years ago

Point E is located at coordinates (-7, -5). Point F is located at the coordinates (-2, 7). What is the length of EF?

Nonamiya [84]

Point E is located at coordinates (-7, -5). Point F is located at the coordinates (-2, 7). What is the length of EF? d is the answer

3 0

3 years ago

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Whats answere y+2=-3 (x - 4)

faust18 [17]

Answer:

Slope = 6.000/2.000 = 3.000

x-intercept = 10/3 = 3.33333

y-intercept = -10/1 = -10.00000

Step-by-step explanation:

Slope is defined as the change in y divided by the change in x. We note that for x=0, the value of y is -10.000 and for x=2.000, the value of y is -4.000. So, for a change of 2.000 in x (The change in x is sometimes referred to as "RUN") we get a change of -4.000 - (-10.000) = 6.000 in y. (The change in y is sometimes referred to as "RISE" and the Slope is m = RISE / RUN)

4 0

3 years ago

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State the domain and range of the relation below.

fgiga [73]

Answer:

The answer you are looking for is A.

Step-by-step explanation:

Remember, the domain is a set of working x values or all possible inputs of a function or two variable relationship. The range is a set of working y values or all possible outputs of a function or two variable relationship. A two variable relationship with more than one output for each input will not be a function in general but will be refered to as inverse.

Now given a set of coordinates for this relation, coordinates with x and y values or inputs and outputs are generally cartesian coordinates represented by (x,y). This is so we know the working x value for each y value, also making it easier to graph it on a coordinate plane or visualize it. x = domain (input of a function) , y = range (output of a function).

All you have to do is sort the x and y values you are given from the coordinates.

For instance, (-1,2) and (4,5) : domain of -1 and 4 [the x values], range of 2, and 5 [the y values].

5 0

3 years ago

Suppose the method of tree ring dating gave the following dates A.D. for an archaeological excavation site. Please show your wor

natita [175]

Answer:

a) $\bar X=\frac{1245+1245+1321+1191+1295+1330+1239+1250+1228}{9}= 1260.444$

b) $s =\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

And if we replace we got:

$s = 45.580$

c) For this case since the sampel size is n=9 <30 we can use the t distribution in order to find the confidence interval.

d) $1260.444-2.306 \frac{45.580}{\sqrt{9}}= 1225.408$

$1260.444+2.306 \frac{45.580}{\sqrt{9}}= 1295.480$

Step-by-step explanation:

For this case we ave the following data:

1245 1245 1321 1191 1295 1330 1239 1250 1228

Part a

We can calculate the sample mean with the following formula:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

And if we replace we got:

$\bar X= \frac{1245+1245+1321+1191+1295+1330+1239+1250+1228}{9}= 1260.444$

Part b

For this case we can use the following formula in order to find the sample standard deviation:

$s =\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

And if we replace we got:

$s = 45.580$

Part c

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

For this case since the sampel size is n=9 <30 we can use the t distribution in order to find the confidence interval.

Part d

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

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

We need to find the degrees of freedom given by:

$df = n-1 = 9-1=8$

Since the Confidence is 0.95 or 95%, the value of $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,8)".And we see that $t_{\alpha/2}=2.306$

Now we have everything in order to replace into formula (1):

$1260.444-2.306 \frac{45.580}{\sqrt{9}}= 1225.408$

$1260.444+2.306 \frac{45.580}{\sqrt{9}}= 1295.480$

8 0

4 years ago