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3 years ago

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20 POINTS HELPPPPPPPPPPPPPPPPPPP

2 answers:

Elenna [48]3 years ago

8 0

The answer is B. The last too are both negative. So they are not true numbers.

ArbitrLikvidat [17]3 years ago

6 0

The correct answer is b

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Two brands of AAA batteries are tested in order to compare their voltage. The data summary can be found below.

garik1379 [7]

Answer:

The 95% confidence interval would be given by $0.281 \leq \mu_1 -\mu_2 \leq 0.529$

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

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".

$\bar X_1 =9.2$ represent the sample mean 1

$\bar X_2 =8.8$ represent the sample mean 2

n1=27 represent the sample 1 size

n2=30 represent the sample 2 size

$\sigma_1 =0.3$ population standard deviation for sample 1

$\sigma_2 =0.1$ population standard deviation for sample 2

$\mu_1 -\mu_2$ parameter of interest.

Solution to the problem

The confidence interval for the difference of means is given by the following formula:

$(\bar X_1 -\bar X_2) \pm z_{\alpha/2}\sqrt{\frac{\sigma^2_1}{n_1}+\frac{\sigma^2_2}{n_2}}$ (1)

The point of estimate for $\mu_1 -\mu_2$ is just given by:

$\bar X_1 -\bar X_2 =9.2-8.8=0.4$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $t_{\alpha/2}=1.96$

Now we have everything in order to replace into formula (1):

$0.4-1.96\sqrt{\frac{0.3^2}{27}+\frac{0.1^2}{30}}=0.281$

$0.4+1.96\sqrt{\frac{6^2}{36}+\frac{7^}{49}}=0.519$

So on this case the 95% confidence interval would be given by $0.281 \leq \mu_1 -\mu_2 \leq 0.529$

6 0

3 years ago

Find the coordinates of P ' if D o, 2.4 (x,y) is applied to the triangle below

guajiro [1.7K]

Answer:

The coordinates of P' are (4.8,-4.8).

Step-by-step explanation:

The rule of dilation $D_{o,2.4}(x,y)$ represent the dilation with scale factor 2.4 and center at origin.

If the scale factor of the dilation is k and the center is (0,0), then

$(x,y)\rightarrow (kx,ky)$

Since the scale factor is 2.4, therefore

$(x,y)\rightarrow (2.4x,2.4y)$

From the given figure it is noticed that the coordinates of P are (2,-2). The coordinates of P' are

$P(2,-2)\rightarrow P'(2.4(2),2.4(-2))$

$P(2,-2)\rightarrow P'(4.8,-4.8)$

Therefore the coordinates of P' are (4.8,-4.8).

3 0

3 years ago

10.125 as a fraction

zubka84 [21]

Answer:

$\frac{81}{8}$

Step-by-step explanation:

$10.125=\frac{10125^{(125}}{1000}=\frac{81}{8}$

6 0

3 years ago

Read 2 more answers

A farmer uses 3/5 of his land to grow cassava, 1/3 of the remainder for yam and the rest for maize. Find the part of the land us

alexira [117]

Answer:

Step-by-step explanation:

Cassava = 1/3 of his land

Remaining after planting Cassava = 1 - 1/3 = 2/3 of his land

Maize = 2/5 x 2/3 = 4/15 of his land

Vegetables = 2/3 - 4/15 = 2/5 of his land

If vegetables = 10 acres

2/5 of his land = 10 acres

1/5 of his land = 10 ÷ 2 = 5 acres

5/5 of his land = 5 x 5 = 25 acres

4 0

3 years ago

Haruka hiked several kilometers in the morning. She hiked only 666 kilometers in the afternoon, which was 25\%25%25, percent les

katen-ka-za [31]

Answer:

She hiked 1,554 kilometers in all.

Step-by-step explanation:

Let the hiking kilometers for morning be x

Given that:

Hiking kilometers in afternoon = 666

According to given condition that afternoon kilometers are 25% less than morning:

x = 666 + 25% of x

By simplifying:

x = 666 + 0.25x

x - 0.25x = 666

0.75x = 666

Dividing both sides by 0.75 we get:

x = 666/0.75

x = 888 kilometers

She hiked 888 kilometers in morning

And

Total = 888 + 666 =1554 km

i hope it will help you!

3 0

3 years ago

Read 2 more answers