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3 years ago

What is a good algebra calculator that is free to use

Mathematics

2 answers:

GarryVolchara [31]3 years ago

8 0

I always use Algebra Mathaway or Math Papa

mixas84 [53]3 years ago

8 0

Try cymath//// it answers your questions for you and shows you the steps

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Express 71/1000 as a decimal

tresset_1 [31]

Answer:

71/1000 as a decimal you have to divide numerator by the denominator of the fraction.

We divide now 71 by 1000 what we write down as 71/1000 and we get 0.071

Step-by-step explanation:

5 0

3 years ago

Evaluate the expression for the given value of the variable. 51+5/8t T= -1/2

Aleksandr [31]

Answer:

811/16 i think

Step-by-step explanation:

6 0

2 years ago

In 2002, the mean age of an inmate on death row was 40.7 years with a standard deviation of 9.6 years according to the U.S. Depa

marissa [1.9K]

Answer:

The 95% confidence interval for the current mean age of death-row inmates is between 42.23 years and 35.57 years.

Step-by-step explanation:

The confidence interval of the mean is given by the next formula:

$\\ \overline{x} \pm z_{1-\frac{\alpha}{2}}\frac{\sigma}{\sqrt{n}}$ [1]

We already know (according to the U.S. Department of Justice):

The (population) standard deviation for this case (mean age of an inmate on death row) has a standard deviation of 9.6 years ( $\\ \sigma = 9.6$ years).
The number of observations for the sample taken is $\\ n = 32$ .
The sample mean, $\\ \overline{x} = 38.9$ years.

For $\\ z_{1-\frac{\alpha}{2}}$ , we have that $\\ \alpha = 0.05$ . That is, the level of significance $\\ \alpha$ is 1 - 0.95 = 0.05. In this case, then, we have that the z-score corresponding to this case is:

$\\ z_{1-\frac{\alpha}{2}} = z_{1-\frac{0.05}{2}} = z_{1-0.025} = z_{0.975}$

Consulting a cumulative standard normal table, available on the Internet or in Statistics books, to find the z-score associated to the probability of, $\\ P(z$ , we have that $\\ z = 1.96$ .

Notice that we supposed that the sample is from a population that follows a normal distribution. However, we also have a value for n > 30, and we already know that for this result the sampling distribution for the sample means follows, approximately, a normal distribution with mean, $\\ \mu$ , and standard deviation, $\\ \sigma_{\overline{x}} = \frac{\sigma}{\sqrt{n}}$ .

Having all this information, we can proceed to answer the question.

Constructing the 95% confidence interval for the current mean age of death-row inmates

To construct the 95% confidence interval, we already know that this interval is given by [1]:

$\\ \overline{x} \pm z_{1-\frac{\alpha}{2}}\frac{\sigma}{\sqrt{n}}$

That is, we have:

$\\ \overline{x} = 38.9$ years.

$\\ z_{1-\frac{\alpha}{2}} = 1.96$

$\\ \sigma = 9.6$ years.

$\\ n = 32$

Then

$\\ 38.9 \pm 1.96*\frac{9.6}{\sqrt{32}}$

$\\ 38.9 \pm 1.96*\frac{9.6}{5.656854}$

$\\ 38.9 \pm 1.96*1.697056$

$\\ 38.9 \pm 3.326229$

Therefore, the Upper and Lower limits of the interval are:

Upper limit:

$\\ 38.9 + 3.326229$

$\\ 42.226229 \approx 42.23$ years.

Lower limit:

$\\ 38.9 - 3.326229$

$\\ 35.573771 \approx 35.57$ years.

In sum, the 95% confidence interval for the current mean age of death-row inmates is between 42.23 years and 35.57 years.

Notice that the "mean age of an inmate on death row was 40.7 years in 2002", and this value is between the limits of the 95% confidence interval obtained. So, according to the random sample under study, it seems that this mean age has not changed.

7 0

3 years ago

How many 1 over 8 isin 1 whole and how many 1/8 are in 3 whole

Black_prince [1.1K]

You divide one by 1/8 to get the first answer.
It is obvious there are 8 pieces of eight in one whole.
Now to get the amount of eights in three wholes, multiply how much is in one whole by 3 to get 2.

4 0

3 years ago

Read 2 more answers

Tessa is cooking steak for her family. She wants to be sure the steak has an internal temperature of at least 160 degrees Fahren

Over [174]

Answer:

Population : all the steaks Tessa can cook

Parameter : minimum internal temperature of 160 degrees Fahrenheit

Sample : two random thermometer readings

Statistic : minimum sample reading of 165 degrees Fahrenheit

Step-by-step explanation:

Let's recall the definitions of these statistical concepts and match it with the information that were provided to us:

Populations can be the complete set of all similar items that exist, in our case, all the steaks that Tessa can cook.
Parameter is is a value that describes a characteristic of an entire population, such as the minimum temperature of the steaks Tessa is cooking in Fahrenheit degrees.
Sample is a subset of the population, in our case, the two random readings of the thermometer Tessa did.
Statistic is a characteristic of a sample, for our problem, it's the minimum reading of 165 degrees Fahrenheit.

3 0

3 years ago