A geologist examines 18 water samples for iron concentration. The mean iron concentration for the sample data is 0.272 cc/cubic meter with a standard deviation of 0.0851. Determine the 99% confidence interval for the population mean iron concentration. Assume the population is approximately normal. Step 1 of 2: Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.

Answer:

The critical value that should be used in constructing the confidence interval is T = 2.898.

The 99% confidence interval for the population mean iron concentration is between 0.214 cc/cubic meter and 0.33 cc/cubic meter.

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 18 - 1 = 17

99% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 17 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.99}{2} = 0.995[/tex]. So we have T = 2.898.

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 2.898\frac{0.0851}{\sqrt{18}} = 0.058[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 0.272 - 0.058 = 0.214 cc/cubic meter.

The upper end of the interval is the sample mean added to M. So it is 0.272 + 0.058 = 0.33 cc/cubic meter.

The 99% confidence interval for the population mean iron concentration is between 0.214 cc/cubic meter and 0.33 cc/cubic meter.

Luna packed two chocolate bars for her trip. One s'mores uses 1/2 of a bar. If she has one s'mores a day, about how many days will the chocolates last?

Complete the sentence.
9 is 36% of

Jacob opened a money-market account. In the first month, he made an initial deposit of $500, and
he plans to contribute an additional $75 every month. The account does not pay any interest.
After how many months will he have a total of $1,475?

Help with these pls

A population numbers 10,000 organisms initially and decreases by 4.1% each year.
Suppose P represents population, and t the number of years of growth. An exponential model for the
population can be written in the form P = a b where
P=

Find the height and area of the polygon. Round your answer to the nearest thousandths (Use exact values until the end).

A shipment of sugar fills 8 containers. If each container holds 2 1/6 tons of sugar, what is the amount of sugar in the entire shipment?

What is the ratio in simplest form between the length of a side in ABCD and the length of its corresponding side in WXYZ?

a.2\3
b.1\2
c.3\4
d.6\5

d. Cloe has 84 packs of potato chips and 86 juice boxes.
He wants to share them equally with all his friends. How
A many friend does Cloe have
? How many packs of chips
and juice boxes will each friend receive? is it LCM or GCF?​

We wish to determine the proportion of small- to medium-sized streams in eastern North Carolina which have runoff from hog farms in order to prepare for issues arising from water quality in the aftermath of hurricanes. A random sample of 174 small- to medium-sized streams is selected and it is found that 100 of them have runoff from hog farms. Which of the following is the value of the parameter of interest in this setting?
a. 0.02322.
b. 0.240.
c. 0.760.
d. the value of the parameter of interest cannot be determined from the given information.

Which function has a greater rate of change?
pls help me lol

Statistic questions

Someone pls help (Becca’s dog walking business started with 1 dog. She walks 2 additional dogs each month.The graph represents the problem. How many dogs does she walk in the third month?)

HELP Easy math easy points look at the photo

The base figure in a mandala design is a nine-pointed star. Find the measure of each arc of the circle circumscribed about the star.

I NEED HELP ASAPPPPP ​

Diane scored 356.789 points Jeff scored 190.499 points how many more points did Diane score than Jeff

243 to the 1/5 power​

I need help with this math assignment ASAP

WILL GIVE BRAINLIEST HELP

Payne saves $2,000 at a yearly simple interest rate of 2%. He earns $280 in interest. How many years did he save his money?

Can u please give me the real answer I really need help☹️

A nurse administers 25 milligrams of a drug to a patient. The amount of the drug, A, in milligrams, left in the patient after thours can be modeled by the function A(t) = 25e 0.354
How many hours will it take for the amount of the drug left in the patient to drop to 0.25 milligrams? Round your answer to the nearest tenth of an hour.
hours
Pls helppp

How can 5 children share 3 cookies equally?

someone pls help I'm genuinely confused

I've literally been trying to figure out all three of these for like two hours now but I can't figure it out

I need help understanding these problems.

solve the rational equation 8-6/x=5+12/x

For which function and interval can the extreme value theorem be applied?
O f(x) =
Х
(x-6)
over the interval [3, 5)
-5
f(x) =
2(x-7)3
over the interval (6,8)
f(x) = 4 tan(Ttx) over the interval [0, 1]
f(x) = 3e' + 1 over the interval (1,3)

Order the sides of each triangle from shortest to longest

The period is . On a coordinate plane, the points on a function curve are shown. The curve crosses the y-axis at (0, 5) and then decreases to the minimum. The minimum is at (0.748, 2) and the maximum is at (1.870, 6). After the green point, the curve increases and then decreases again. A green point is at y = 4.