Find cos 0

In a sample of nequals16 lichen specimens, the researchers found the mean and standard deviation of the amount of the radioacti

GuDViN [60]

Answer:

(a) The confidence level desired by the researchers is 95%.

(b) The sampling error is 0.002 microcurie per millilitre.

(c) The sample size necessary to obtain the desired estimate is 25.

Step-by-step explanation:

The mean and standard deviation of the amount of the radioactive element, cesium-137 present in a sample of n = 16 lichen specimen are:

$\bar x=0.009\\s=0.005$

Now it is provided that the researchers want to increase the sample size in order to estimate the mean μ to within 0.002 microcurie per millilitre of its true value, using a 95% confidence interval.

The (1 - α)% confidence interval for population mean (μ) is:

$CI=\bar x\pm z_{\alpha/2}\times \frac{s}{\sqrt{n}}$

(a)

The confidence level is the probability that a particular value of the parameter under study falls within a specific interval of values.

In this case the researches wants to estimate the mean using the 95% confidence interval.

Thus, the confidence level desired by the researchers is 95%.

(b)

In case of statistical analysis, during the computation of a certain statistic, to estimate the value of the parameter under study, certain error occurs which are known as the sampling error.

In case of the estimate of parameter using a confidence interval the sampling error is known as the margin of error.

In this case the margin of error is 0.002 microcurie per millilitre.

(c)

The margin of error is computed using the formula:

$MOE=z_{\alpha/2}\times \frac{s}{\sqrt{n}}$

The critical value of z for 95% confidence level is:

$z_{\alpha/2}=z_{0.05/2}=z_{0.025}=1.96$

*Use a z-table.

$MOE=z_{\alpha/2}\times \frac{s}{\sqrt{n}}$

$0.002=1.96\times \frac{0.005}{\sqrt{n}}$

$n=[\frac{1.96\times 0.005}{0.002}]^{2}$

$=(4.9)^{2}\\=24.01\\\approx 25$

Thus, the sample size necessary to obtain the desired estimate is 25.

6 0

4 years ago

How many edges does a dodecahedron have ?

balu736 [363]

Answer:

12

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers

The sum of 2 numbers is 30 and the difference is 10. What are the two numbers.

maw [93]

Answer:

20 + 10 = 30

Step-by-step explanation:

The sum of x and y is 30. In other words, x plus y equals 30 and can be written as equation A:

x + y = 30

The difference between x and y is 10. In other words, x minus y equals 10 and can be written as equation B:

x - y = 10

Now solve equation B for x to get the revised equation B:

x - y = 10

x = 10 + y

Then substitute x in equation A from the revised equation B and then solve for y:

x + y = 30

10 + y + y = 30

10 + 2y = 30

2y = 20

y = 10

Now we know y is 10. Which means that we can substitute y for 10 in equation A and solve for x:

x + y = 30

x + 10 = 30

X = 20

Summary: The sum of two numbers is 30 and their difference is 10. What are the two numbers? Answer: 20 and 10 as proven here:

Sum: 20 + 10 = 30

Difference: 20 - 10 = 10

4 0

3 years ago

Read 2 more answers

Find the approximate perimeter of polygon CODIFYCODIFYC, O, D, I, F, Y plotted below.

klio [65]

Answer:

49.81

Step-by-step explanation:

the formula I used is distance= $\sqrt{(x_{2}-x_{1})+(y_{2}-y_{1})}$

Lets say we are finding the distance from c to y

c=(-6,9)

y=(5,9)

cy= $\sqrt{(5-(-6))^{2}+(9-9)^2 }$

cy= $\sqrt{(11)^2+(0)^2}$

cy= $\sqrt{121+0}$

cy= $\sqrt{121}$

cy=11

And you can find the distance between y and i, i and d, d and o, o and c, using the same formula.

After solving the distance of all I got

yi=16.55294536

id=1

do=9.219544457

oc=12.04159458

After you add them all up you get 49.8140844 which rounded to the nearest hundredth is 48.81.

Thank you and I hope that is helpful.

Sorry that is actually wrong

Check out the other answer.

4 0

4 years ago

Read 2 more answers

A circle is shown. Identify the center of the circle.

Vlada [557]

Step-by-step explanation:STEP 1: Draw two straight, intersecting tangent lines onto the circle. The lines can be completely random. However, the process will be easier if you make them roughly square or rectangular.

STEP 2: Translate both of the lines to the other side of the circle. You will end up with four tangent lines forming a parallelogram or a rough rectangle.

STEP 3: Draw the diagonals of the parallelogram. The point where these diagonal lines intersect is the circle's center.

STEP 4: Check the accuracy of the center with a compass. The center should be on target as long as you didn't slip while translating the lines or when drawing the diagonals. Feel free to erase the parallelogram and diagonal lines.

5 0

4 years ago