All categories

3 years ago

Which information do you know is true from the diagram? Check all that apply.

Mathematics

1 answer:

FinnZ [79.3K]3 years ago

8 0

Answer: <ABD is a right angle and m<ABD = 90°

Step-by-step explanation:

You might be interested in

In a manufacturing process, we are interested in measuring the average length of a certain type of bolt. Past data indicate that

Goryan [66]

Answer:

We need a sample size of 600 or higher in order to make us 95 percent confident that the sample mean bolt length is within .02 inches of the true mean bolt length

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.025 = 0.975$ , so $z = 1.96$

Now, we find the margin of error M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

How many bolts should be sampled in order to make us 95 percent confident that the sample mean bolt length is within .02 inches of the true mean bolt length?

We need a sample size of n or higher, when $M = 0.02, \sigma = 0.25$ . So

$M = z*\frac{\sigma}{\sqrt{n}}$

$0.02 = 1.96*\frac{0.25}{\sqrt{n}}$

$0.02\sqrt{n} = 0.49$

$\sqrt{n} = \frac{0.49}{0.02}$

$\sqrt{n} = 24.5$

$\sqrt{n}^{2} = (24.5)^{2}$

$n = 600$

We need a sample size of 600 or higher in order to make us 95 percent confident that the sample mean bolt length is within .02 inches of the true mean bolt length

4 0

3 years ago

A study was conducted to determine whether magnets were effective in treating pain. The values represent measurements of pain us

gregori [183]

Answer and Step-by-step explanation: The null and alternative hypothesis for this test are:

$H_{0}: s_{1}^{2} = s_{2}^{2}$

$H_{a}: s_{1}^{2} > s_{2}^{2}$

To test it, use F-test statistics and compare variances of each treatment.

Calculate F-value:

$F=\frac{s^{2}_{1}}{s^{2}_{2}}$

$F=\frac{1.26^{2}}{0.93^{2}}$

$F=\frac{1.5876}{0.8649}$

F = 1.8356

The <u>critical value of F</u> is given by a F-distribution table with:

degree of freedom (row): 20 - 1 = 19

degree of freedom (column): 20 - 1 = 19

And a significance level: α = 0.05

$F_{critical}$ = 2.2341

Comparing both values of F:

1.856 < 2.2341

i.e. F-value calculated is less than F-value of the table.

Therefore, failed to reject $H_{0}$ , meaning there is <u>no sufficient data to support the claim</u> that sham treatment have pain reductions which vary more than for those using magnets treatment.