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3 years ago

ANSWER ASAP PLEASE WORTH 15 POINTS

Mathematics

2 answers:

dimulka [17.4K]3 years ago

4 0

Answer is -4 im 100% sure

Sloan [31]3 years ago

3 0

Answer:

-4

Step-by-step explanation:

-8 × ? = 32

-8 × -4 = 32

Therefore the correct answer is - 4

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A simple random sample of size nequals81 is obtained from a population with mu equals 83 and sigma equals 27. (a) Describe the

Ivanshal [37]

Answer:

a) $\bar X \sim N (\mu, \frac{\sigma}{\sqrt{n}})$

With:

$\mu_{\bar X}= 83$

$\sigma_{\bar X}=\frac{27}{\sqrt{81}}= 3$

b) $z= \frac{89-83}{\frac{27}{\sqrt{81}}}= 2$

$P(Z>2) = 1-P(Z$

c) $z= \frac{75.65-83}{\frac{27}{\sqrt{81}}}= -2.45$

$P(Z$

d) $z= \frac{89.3-83}{\frac{27}{\sqrt{81}}}= 2.1$

$z= \frac{79.4-83}{\frac{27}{\sqrt{81}}}= -1.2$

$P(-1.2$

Step-by-step explanation:

For this case we know the following propoertis for the random variable X

$\mu = 83, \sigma = 27$

We select a sample size of n = 81

Part a

Since the sample size is large enough we can use the central limit distribution and the distribution for the sampel mean on this case would be:

$\bar X \sim N (\mu, \frac{\sigma}{\sqrt{n}})$

With:

$\mu_{\bar X}= 83$

$\sigma_{\bar X}=\frac{27}{\sqrt{81}}= 3$

Part b

We want this probability:

$P(\bar X>89)$

We can use the z score formula given by:

$z = \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}$

And if we find the z score for 89 we got:

$z= \frac{89-83}{\frac{27}{\sqrt{81}}}= 2$

$P(Z>2) = 1-P(Z$

Part c

$P(\bar X$

We can use the z score formula given by:

$z = \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}$

And if we find the z score for 75.65 we got:

$z= \frac{75.65-83}{\frac{27}{\sqrt{81}}}= -2.45$

$P(Z$

Part d

We want this probability:

$P(79.4 < \bar X < 89.3)$

We find the z scores:

$z= \frac{89.3-83}{\frac{27}{\sqrt{81}}}= 2.1$

$z= \frac{79.4-83}{\frac{27}{\sqrt{81}}}= -1.2$

$P(-1.2$

8 0

3 years ago

What is the equation of the line graphed below ?

makvit [3.9K]

The answer is A. y = -2/5

4 0

3 years ago

Best known for its testing program, ACT, Inc., also compiles data on a variety of issues in education. In 2004 the company repor

GarryVolchara [31]

Answer:

$\mu_p -\sigma_p = 0.74-0.0219=0.718$

$\mu_p +\sigma_p = 0.74+0.0219=0.762$

68% of the rates are expected to be betwen 0.718 and 0.762

$\mu_p -2*\sigma_p = 0.74-2*0.0219=0.696$

$\mu_p +2*\sigma_p = 0.74+2*0.0219=0.784$

95% of the rates are expected to be betwen 0.696 and 0.784

$\mu_p -3*\sigma_p = 0.74-3*0.0219=0.674$

$\mu_p +3*\sigma_p = 0.74+3*0.0219=0.806$

99.7% of the rates are expected to be betwen 0.674 and 0.806

Step-by-step explanation:

Check for conditions

For this case in order to use the normal distribution for this case or the 68-95-99.7% rule we need to satisfy 3 conditions:

a) Independence : we assume that the random sample of 400 students each student is independent from the other.

b) 10% condition: We assume that the sample size on this case 400 is less than 10% of the real population size.

c) np= 400*0.74= 296>10

n(1-p) = 400*(1-0.74)=104>10

So then we have all the conditions satisfied.

Solution to the problem

For this case we know that the distribution for the population proportion is given by:

$p \sim N(p, \sqrt{\frac{p(1-p)}{n}})$

So then:

$\mu_p = 0.74$

$\sigma_p =\sqrt{\frac{0.74(1-0.74)}{400}}=0.0219$

The empirical rule, also referred to as the three-sigma rule or 68-95-99.7 rule, is a statistical rule which states that for a normal distribution, almost all data falls within three standard deviations (denoted by σ) of the mean (denoted by µ). Broken down, the empirical rule shows that 68% falls within the first standard deviation (µ ± σ), 95% within the first two standard deviations (µ ± 2σ), and 99.7% within the first three standard deviations (µ ± 3σ).

$\mu_p -\sigma_p = 0.74-0.0219=0.718$

$\mu_p +\sigma_p = 0.74+0.0219=0.762$

68% of the rates are expected to be betwen 0.718 and 0.762

$\mu_p -2*\sigma_p = 0.74-2*0.0219=0.696$

$\mu_p +2*\sigma_p = 0.74+2*0.0219=0.784$

95% of the rates are expected to be betwen 0.696 and 0.784

$\mu_p -3*\sigma_p = 0.74-3*0.0219=0.674$

$\mu_p +3*\sigma_p = 0.74+3*0.0219=0.806$

99.7% of the rates are expected to be betwen 0.674 and 0.806

5 0

3 years ago

Teds science class collects aluminum cans to sell to the recycling center. the center pays a fixed amount for each kilogram of a

tatuchka [14]

The Center Pays<span> $0.002 For </span><span>Each Kilogram</span>

3 0

2 years ago

What is the constant of 2x+3y+6

vekshin1

Answer:

Step-by-step explanation:

Constants are any numbers that don't change.

2x + 3y + 6

Since "6" is the only number here, that is the only constant.

Best of Luck!

3 0

3 years ago

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