Can someone help plss

Dual-energy X-ray absorptiometry (DXA) is a technique for measuring bone health. One of the most common measures is total body b

sesenic [268]

Answer:

$\bar d=\frac{\sum_{i=1}^n d_i}{n}=-0.001$

$s=\sqrt{\frac{\sum_{i=1}^n (x_i -\bar X)^2}{n-1}}=0.0095$

-The sample is too small to make judgments about skewness or symmetry.

H0: $\mu_{1}=\mu_{2}$

H1: $\mu_{1} \neq \mu_{2}$

$t=\frac{1.173-1.174}{\sqrt{\frac{0.1506^2}{8}+\frac{0.1495^2}{8}}}=-0.013$

$p_v =2*P(t_{(14)}$

So the p value is a very high value and using any significance level for example $\alpha=0.05, 0,1,0.15$ always $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and a we don't have a significant difference between the two means.

Step-by-step explanation:

First we need to find the difference defined as:

(Operator 1 minus Operator 2)

d1=1.326-1.323=0.003 d2=1.337-1.322=0.015

d3=1.079-1.073=0.006 d4=1.229-1.233=-0.004

d5=0.936-0.934=0.002 d6=1.009-1.019=-0.01

d7=1.179-1.184=-0.005 d8=1.289-1.304=-0.015

Now we can calculate the mean of differences given by:

$\bar d=\frac{\sum_{i=1}^n d_i}{n}=-0.001$

And for the sample deviation we can use the following formula:

$s=\sqrt{\frac{\sum_{i=1}^n (x_i -\bar X)^2}{n-1}}=0.0095$

Describe the distribution of these differences using words. (which one is correct)

We can plot the distribution of the differences with the folowing code in R

differences<-c(0.003,0.015,0.006,-0.004,0.002,-0.01,-0.005,-0.015)

hist(differences)

And we got the image attached. And we can see that the distribution is right skewed but we don't have anough info to provide a conclusion with just 8 differnences.

-The sample is too small to make judgments about skewness or symmetry.

Use a significance test to examine the null hypothesis that the two operators have the same mean. Give the test statistic. (Round your answer to three decimal places.)

$\bar X_{1}=1.173$ represent the mean for the operator 1

$\bar X_{2}=1.174$ represent the mean for the operator 2

$s_{1}=0.1506$ represent the sample standard deviation for the operator 1

$s_{2}=0.1495$ represent the sample standard deviation for the operator 2

$n_{1}=8$ sample size for the operator 1

$n_{2}=8$ sample size for the operator 2

t would represent the statistic (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to check if the means for the two groups are the same, the system of hypothesis would be:

H0: $\mu_{1}=\mu_{2}$

H1: $\mu_{1} \neq \mu_{2}$

If we analyze the size for the samples both are less than 30 so for this case is better apply a t test to compare means, and the statistic is given by:

$t=\frac{\bar X_{1}-\bar X_{2}}{\sqrt{\frac{s^2_{1}}{n_{1}}+\frac{s^2_{2}}{n_{2}}}}$ (1)

t-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

Calculate the statistic

We can replace in formula (1) like this:

$t=\frac{1.173-1.174}{\sqrt{\frac{0.1506^2}{8}+\frac{0.1495^2}{8}}}=-0.013$

Statistical decision

For this case we don't have a significance level provided $\alpha$ , but we can calculate the p value for this test. The first step is calculate the degrees of freedom, on this case:

$df=n_{1}+n_{2}-2=8+8-2=14$

Since is a bilateral test the p value would be:

$p_v =2*P(t_{(14)}$

So the p value is a very high value and using any significance level for example $\alpha=0.05, 0,1,0.15$ always $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and a we don't have a significant difference between the two means.

8 0

3 years ago

Is the following statement a good definition? Why? An integer is divisible by 100 if and only if its last two digits are zeros.

nikitadnepr [17]

The given statement is An integer is divisible by 100 if and only if its last two digits are zeros.

The two conditional statements that can be made are:

1) If an integer is divisible by 100 its last two digits are zeros.

This is a true statement. If a number is divisible by 100, it means 100 must be a factor of that number. When 100 will be multiplied by the remaining factors, the number will have the last two digits zeros.

<h3>What happen when last two digit of the number are 0?</h3>

2) If the last two digits of an integer are zeros, it is divisible by 100.

This is also true. If the last two digits are zeros, this means 100 is a factor of the integer. So the number will be divisible by 100.

Therefore, the two conditional statements that are formed are both true.

So, option A is the correct answer.

Yes, it is. When the definition is separated into two conditional statements, both of the statements are true.

To learn more about the integer visit:

brainly.com/question/17695139

#SPJ1

4 0

2 years ago

Read 2 more answers

Sue had 5 identical bags of candy to share with the crew. Twenty-five pieces of candy disappeared. Ted had 4 bags with the same

inna [77]

Answer:

Each bag originally had 35 pieces of candy

Step-by-step explanation:

Since the bags are identical, Let them Number of candies in each bag sue had be x. Thus, she had 5x candies. Since she lost 25 pieces, then she now has;

5x - 25 candies left.

We are told that Ted had 4 bags with the same number of candies like Sue had. Thus, he has 4x candies.

He mysteriously found 10 additional pieces. Total Ted now has is;. 4x + 10

Finally, we are told that Sue and Ted now have an equal number of candies.

Thus;

5x - 25 = 4x + 10

Rearranging, we have;

5x - 4x = 25 + 10

x = 35

Thus, each bag originally had 35 pieces of candy

3 0

3 years ago

The average maximum monthly temperature in Campinas, Brazil is 29.9 degrees Celsius. The standard deviation in maximum monthly t

velikii [3]

Answer:

3.84% of months would have a maximum temperature of 34 degrees or higher

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 29.9, \sigma = 2.31$

What percentage of months would have a maximum temperature of 34 degrees or higher?

This is 1 subtracted by the pvalue of Z when X = 34. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{34 - 29.9}{2.31}$

$Z = 1.77$

$Z = 1.77$ has a pvalue of 0.9616

1 - 0.9616 = 0.0384

3.84% of months would have a maximum temperature of 34 degrees or higher

8 0

3 years ago

Calvin's plane is flying at a speed of 600 miles per hour. If y represents the distance the plane has traveled and z represents

Ksenya-84 [330]

Answer:

D

Step-by-step explanation:

the answer is d because the amount of speed changes the total amount of distance that he travels in time

7 0

3 years ago