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3 years ago

What is 13x= 2x+26-12.5?

Mathematics

2 answers:

ololo11 [35]3 years ago

7 0

13x = 2x + 26 - 12.5

Subtract 26 and 12.5...

13x = 2x + 13.5

Subtract 2x....

11x = 13.5

x = 1.23

Ulleksa [173]3 years ago

5 0

The answer would be 6, 0.5

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The average body temperature of all healthy adults is 98.6 F. A doctor takes a random sample of 100 healthy adults and records t

Yuliya22 [10]

Answer:

Explained below.

Step-by-step explanation:

A parameter is a valuable element of statistical analysis. It denotes the characteristics that are used to define a given population. It is used to define a particular attribute of the population. For instance, population mean, population standard deviation, population proportion and so on.

The parameter of interest is the average body temperature of all healthy adults, μ = 98.6°F.

While making a statistical conclusion about the population under study, the parameter value is unknown. This is because it would not be possible to gather data from every single member of the population. So a sample is selected from the population to derive a conclusion about the parameter.

A statistic is the value of the characteristics that are computed using this sample. For instance, sample mean, sample standard deviation, sample proportion and so on.

The statistic is the average body temperature of 100 randoly selected healthy adults, $\bar x=98.2^{o}F$ .

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3 years ago

Suppose that 20% of the subscribers of a cable television company watch the shopping channel at least once a week. The cable com

riadik2000 [5.3K]

Answer:

4.01% probability that the cable company will keep the shopping channel.

Step-by-step explanation:

For each subscriber, there are only two possible outcomes. Either they watch the shopping channel at least once a week, or they do not. This means that we can solve this problem using the binomial probability distribution.

However, we are working with samples that are considerably big. So i am going to aproximate this binomial distribution to the normal.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

In this problem, we have that:

$n = 100, p = 0.20$

$E(X) = 100*0.20 = 20$

$\sqrt{V(X)} = \sqrt{100*0.20*0.80} = 4$

The cable company has decided to keep the shopping channel if the sample proportion is greater than 0.27. What is the approximate probability that the cable company will keep the shopping channel, even though the true proportion who watch it is only 0.20?

This probability is 1 subtracted by the pvalue of Z when $X = 0.27*100 = 27$ . So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{27 - 20}{4}$

$Z = 1.75$

$Z = 1.75$ has a pvalue of 0.9599.

So there is a 1-0.9599 = 0.0401 = 4.01% probability that the cable company will keep the shopping channel.

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3 years ago

What is the product? (2x - 1)(x+4) 2x?-4 2x+4 2x+7-4 2x? - 7x-4

damaskus [11]

The answer is :

2x^2 + 7x - 4

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3 years ago

a geologist noticed that land along a fault line moved 24.8 cm over 175 yrs on average how much did the land move each year

Nata [24]

24.8 cm ÷ 175= 0.141... or 0.14 cm.
The answer is 0.14 cm

6 0

3 years ago

Read 2 more answers

A leading bank is coming up with an investment that pays 8 percent interest compounded semiannually. What is the investment's ef

uranmaximum [27]

The effective rate is calculated in the following way:
$r = {(1 + \frac{i}{n} )}^{n} - 1$
where r is the effective annual rate, i the interest rate, and n the number of compounding periods per year (for example, 12 for monthly compounding).
our compounding period is 2 since the bank pays us semiannually(two times per year) and our interest rate is 8%
so lets plug in numbers:
$r = {(1 + \frac{8\%}{2}) }^{2} - 1 \\ r = {(1 + \frac{1}{25}) }^{2} - 1 \\ r = \frac{676}{625} - 1 \\ r = 0.0816 \: or \: 8.16\%$

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3 years ago