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3 years ago

How to find average.

Mathematics

2 answers:

larisa [96]3 years ago

6 0

Add up all of the numbers and then divide by the amount of numbers you have, basically the sum divided by the amount. :)

Ray Of Light [21]3 years ago

3 0

Answer:

Add up all the numbers then divided by how many numbers there is and the you'll get your answer.

Example:

70+80+75+85+90=400

400 divided by 5=80

So 80 is my answer

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ccording to the U.S. National Weather Service, at any given moment of any day, approximately 1000 thunderstorms are occurring wo

viva [34]

Answer:

The critical value of z for 99% confidence interval is 2.5760.

The 99% confidence interval for population mean number of lightning strike is (7.83 mn, 8.37 mn).

Step-by-step explanation:

Let X = number of lightning strikes on each day.

A random sample of n = 23 days is selected to observe the number of lightning strikes on each day.

The random variable X has a sample mean of, $\bar x=8.1\ mn$ and the population standard deviation, $\sigma=0.51\ mn$ .

The (1 - α)% confidence interval for population mean μ is:

$CI=\bar x\pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$

Compute the critical value of z for 99% confidence interval is:

$z_{\alpha/2}=z_{0.01/2}=z_{0.005}=2.5760$

*Use a z-table.

The critical value of z for 99% confidence interval is 2.5760.

Compute the 99% confidence interval for population mean number of lightning strike as follows:

$CI=\bar x\pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}\\=8.1\pm2.5760\times\frac{0.51}{\sqrt{23}}\\=8.1\pm0.2738\\=(7.8262, 8.3738)\\\approx(7.83, 8.37)$

Thus, the 99% confidence interval for population mean number of lightning strike is (7.83 mn, 8.37 mn).

The 99% confidence interval for population mean number of lightning strike implies that the true mean number of lightning strikes lies in the interval (7.83 mn, 8.37 mn) with 0.99 probability.

3 0

3 years ago

I will give you 50 point please help and get. it right

natita [175]

6)The experimental probability is 39%.(39/100(100)).

7) The theoretical probability is theoretical. This is when something should happen without taking external forces into account. Experimental probability is taking the external forces into account which is why the probability is not as clean cut.

The theoretical probability should be 33%.
The experimental probability is actually 39%.

4 0

3 years ago

When reading a book, Charlie made a list by writing down the page number of the last page he finished reading at the end of each

Assoli18 [71]

Answer:

No. of pages he read by the end of the 8th day = 425

Step-by-step explanation:

Charlie started from page 1 and read the same number of pages each day. Suppose x is the number of pages he read each day, the last page he read on the first day would be:

Last page for day 1 = 1 + x

This would be the first number he noted on the list.

The second page number can be determined by adding the number of pages he read to the last page for day 1.

Last page for day 2 = 1 + x + x

= 1 + 2x

Similarly, the last page he read on the third day is:

Last page for day 3 = 1 + 3x. Similarly,

Last page for day 4 = 1 + 4x

Last page for day 5 = 1 + 5x

Last page for day 6 = 1 + 6x

Last page for day 7 = 1 + 7x

Last page for day 8 = 1 + 8x

His Mom added all of the page numbers and got a total of 432. So,

432 = 1+x + 1+2x + 1+3x + 1+4x + 1+5x + 1+6x + 1+7x + 1+8x

432 = 8 + 8x

8x = 432-8

8x = 424

x = 424/8

x = 53

By the end of the 8th day he actually read 1 + 8x pages. Substituting the value of x in this expression, we get:

No. of pages he read by the end of the 8th day = 1 + 8(53)

= 1 + 424

No. of pages he read by the end of the 8th day = 425

4 0

4 years ago

What is -38/-5 as a decimal?

sesenic [268]

Divide -38 by -5
The negatives cancel out since a negative divided by a negative is a positive.
7.6

5 0

3 years ago

Question is shown below.

Andrei [34K]

ANSWER

D. 4 minutes 40 seconds

EXPLANATION

The given data set showing the number of seconds of each song the playlist is:

283,204,198,229,173,230,168,236,215,204

Let the length of the 11th song be x.

Because he wants the mean to be 3 minutes 40 seconds, which is equal to 220 seconds, we write and solve the following equation for x.

$\frac{283 + 204 + 198 + 229 + 173 + 230 + 168 + 236 + 215 + 204 + x}{11} = 220$

$\frac{2140 + x}{11} = 220$

$2140 + x = 2420$

$x = 2420 - 2140$

$x = 280$

We convert 280 seconds to minutes.

$\frac{280}{60} = 4 \frac{2}{3} = 4mins : 40 sec$

The correct choice is D

3 0

3 years ago