PLEASE HELP ILL GIVE U BRAINLEST PLUS 50 POINTS IF U GET IT RIGHT

The cost of cementing 30 m² of floor area is $810. How much will it

Y_Kistochka [10]

Answer:

The answer is 1485 m^2

Step-by-step explanation:

27 per m^2 so 27 times 55 = 1485 m^2

6 0

3 years ago

Read 2 more answers

2(n2 + 1) – 3(n2 – 3) + 3(2n2 – 2), n=(1/4)

IceJOKER [234]

]Answer:

$5\frac{5}{16}$

Step-by-step explanation:

Substitute the value of the variable into the equation and simplify.

$2(\frac{1}{4} ^{2} +1-3(\frac{1}{4} ^{2} -3)+3((2*\frac{1}{4}^{2} )-2)$

Solve it out.

Multiply / divide / add / subtract everything out.

4 0

3 years ago

Please answer this correctly

jolli1 [7]

Answer:

6 times

Step-by-step explanation:

1/9 chance you get the orange marble. If you pick 54 times, you can expect to get the orange marble 6 times.

5 0

3 years ago

Find the following probabilities based on the standard normal variable Z. (You may find it useful to reference the z table

hammer [34]

Answer:

Step-by-step explanation:

a. P(Z > 1.12) = 1-N(1.12) = 1-0.8686431=0.1313569

b. P(Z S-2.35) => P(Z <= 2.35) = 0.009386706

(please check interpretation of question b)

c. POSZ s 1.34) => P(0 <= Z <= 1.34) = 0.9098773 - 0.5 = 0.4098773

(please check interpretation of question c)

d. P(-0.8 sz s 2.44) => P(-0.8 <= 2.44) = 0.9926564 - 0.2118554 = 0.780801

(please check interpretation of question d)

7 0

3 years ago

Our environment is very sensitive to the amount of ozone in the upper atmosphere. The level of ozone normally found is 4.6 parts

kirill115 [55]

Answer:

$z=\frac{4.5-4.6}{\frac{1.1}{\sqrt{860}}}=-2.666$

$p_v =2*P(Z$

If we compare the p value and the significance level given $\alpha=0.02$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean is different from 4.6 at 2% of signficance.

Step-by-step explanation:

Data given and notation

$\bar X=4.5$ represent the sample mean

$\sigma=1.1$ represent the population standard deviation

$n=860$ sample size

$\mu_o =4.6$ represent the value that we want to test

$\alpha=0.02$ represent the significance level for the hypothesis test.

z would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is equal or not to 4.6, the system of hypothesis would be:

Null hypothesis: $\mu = 4.6$

Alternative hypothesis: $\mu \neq 4.6$

If we analyze the size for the sample is > 30 and we know the population deviation so is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{4.5-4.6}{\frac{1.1}{\sqrt{860}}}=-2.666$

P-value

Since is a two sided test the p value would be:

$p_v =2*P(Z$

Conclusion

If we compare the p value and the significance level given $\alpha=0.02$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean is different from 4.6 at 2% of signficance.

5 0

3 years ago