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3 years ago

Show how to use known facts to find 6 x 9. Explain how you chose the facts you did

Mathematics

2 answers:

vesna_86 [32]3 years ago

8 0

6
9
×__
54. or u can do 6×9 =54 so u can do it either way or do the 9 trick

and the fact is

scZoUnD [109]3 years ago

3 0

The answer is 54 because 6 times 9 is 54

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23. A certain type of gasoline is supposed to have a mean octane rating of at least 90. Suppose measurements are taken on of 5 r

Nostrana [21]

Answer:

a) $p_v =P(Z$

b) Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

c) $P(\bar X >90)=1-P(Z$

$1-P(Z$

d) For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

Step-by-step explanation:

Previous concepts and data given

The margin of error is the range of values below and above the sample statistic in a confidence interval.

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".

We can calculate the sample mean and deviation with the following formulas:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$s=\sqrt{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}$

$\bar X=88.96$ represent the sample mean

$s=1.011$ represent the sample standard deviation

n=5 represent the sample selected

$\alpha$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is less than 90, the system of hypothesis would be:

Null hypothesis: $\mu \geq 90$

Alternative hypothesis: $\mu < 90$

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t 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:

$z=\frac{88.96-90}{\frac{0.8}{\sqrt{5}}}=-2.907$

Part a

P-value

First we need to calculate the degrees of freedom given by:

$df=n-1=5-1 = 4$

Then since is a left tailed test the p value would be:

$p_v =P(Z$

Part b

Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

Part c

We want this probability:

$P(\bar X$

The best way to solve this problem is using the normal standard distribution and the z score given by:

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

If we apply this formula to our probability we got this:

$P(\bar X >90)=1-P(Z$

$1-P(Z$

Part d

For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

7 0

3 years ago

Get all of them and get brainliest

Marina86 [1]

1. 21,150
2. 2.5193
3. 27.98
4. 11,100

8 0

3 years ago

Determine the domain and range of the function represented by the graph below.

Alenkasestr [34]

Answer:

C. Domain: −2≤x≤2; Range: −2≤y≤2

Step-by-step explanation:

7 0

2 years ago

Please help 7th grade math

Thepotemich [5.8K]

Answer:

x=20, g=100, f=80

Step-by-step explanation:

when ever somthing is suplementary it means the the answer will euqal to 180 degrees. That means your equation is going to be

3x+40+5x-20=180

8x+20=180

8x=160

x=20

Finding g

3(20)+40

60+40

g=100

FInding f

5(20)-20

100-20

f=80

8 0

3 years ago

I WILL MARK YOU BRAINLIEST PLS HELP!!! The image below shows two dilated figures with lines AB and A’B’ drawn. If the larger fig

geniusboy [140]

Answer:

Lines AB and A'B' are similar, line A'B' being three times the size of line AB. They would not be congruent since a dilation isn't a rigid transformation but they would be similar. Their lengths would also be expressed in the form of a ratio which would be 1:3 if you do AB to A'B' and 3:1 if you do A'B' to AB. Hope this helped! :)

Step-by-step explanation:

The relationship between two lines AB and A’B’ is A'B'=3AB.

It is given that in the given figure larger figure was dilated using a scale factor of 3. It means the smaller and larger figures are similar and there corresponding sides are in the ratio 1:3.

The line AB connecting the two points of the smaller figure and line A'B' connecting the two points of the larger figure.

Since A'B' is corresponding line segment of AB in larger figure, therefore the ratio of AB to A'B' is 1:3.

By cross multiplication we get

The length of segment A'B' is 3 times of AB.

MARK ME BRAINLIEST!

6 0

2 years ago