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2 years ago

Helphelpme ahhh helpmme

Mathematics

2 answers:

Mrrafil [7]2 years ago

8 0

Answer:

E A C B

Step-by-step explanation:

nlexa [21]2 years ago

3 0

Answer:

1 is E

2 is A

3 is C

4 is D

Step-by-step explanation:

You might be interested in

As the sample size becomes larger, the sampling distribution of the sample mean approaches a _____. a. binomial distribution b.

kkurt [141]

Answer:

c. normal probability distribution

Step-by-step explanation:

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean $\mu = p$ and standard deviation $s = \sqrt{\frac{p(1-p)}{n}}$

In this question:

By the Central Limit Theorem, it is a normal distribution, so option c.

7 0

2 years ago

A roped-off area of width x is created around a 30- by 10-foot rectangular museum display of Native American artifacts. The comb

Monica [59]

Answer: $4x^{2}+80x-500=0$

Step-by-step explanation:

1. You know that:

- The roped-off area whose width is represented with <em>x,</em> it is created around a rectangular museum.

- The dimensions of the rectangular museum are: 30 ft by 10 ft.

- The combined area of the display and the roped-off area is 800 ft².

2. The area of the rectangular museum can be calculated with:

$A=l*w$

Where $l$ is the lenght and $w$ is the width.

You have that the lenght and the width in feet are:

$l=30\\w=10$

3. Let's call $x$ the width of the roped-off area. Then, the combined area is:

$A_c=l_c*w_c$

Where

$A_c=800$

$l_c=l+x+x=30+2x$

$w_c=w+x+x=10+2x$

4. Substitute values and simplify. Then:

$800=(30+2x)(10+2x)$

$800=300+60x+20x+4x^{2}\\4x^{2}+80x-500=0$

5 0

3 years ago

In a recent year, the ACT scores for the math portion of the test were normally distributed, with a mean of 21.1 and a standard

Natali5045456 [20]

Answer:

a) $P(X$

And we can find this probability using the normal standard table or excel:

$P(z$

b) $P(19$

And we can find this probability with this difference:

$P(-0.396$

And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.

$P(-0.396$

c) $P(X>26)=P(\frac{X-\mu}{\sigma}>\frac{26-\mu}{\sigma})=P(Z>\frac{26-21.1}{5.3})=P(z>0.925)$

And we can find this probability using the complement rule and the normal standard table or excel:

$P(z>0.925)=1- P(Z$

d) We can consider unusual events values above or below 2 deviations from the mean

$Lower = \mu -2*\sigma = 21.1 -2*5.3 =10.5$

A value below 10.5 can be consider as unusual

$Upper = \mu +2*\sigma = 21.1 +2*5.3 =31.7$

A value abovr 31.7 can be consider as unusual

Step-by-step explanation:

Previous concepts

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".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Part a

Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:

$X \sim N(21.1,5.3)$