Ask question

Ask question

All categories

3 years ago

6

A geologist examines 6 seawater samples for lead concentration. The mean lead concentration for the sample data is 0.903 cc/cubi

c meter with a standard deviation of 0.0566 . Determine the 95% confidence interval for the population mean lead concentration. Assume the population is approximately normal.
Step 2 of 2 :

Construct the 95% confidence interval. Round your answer to three decimal places.

1 answer:

Gnesinka [82]3 years ago

7 0

Answer:

Step-by-step explanation:

We want to determine a 95% confidence interval for the mean lead concentration of sea water samples

Number of samples. n = 6

Mean, u = 0.903 cc/cubic meter

Standard deviation, s = 0.0566

For a confidence level of 95%, the corresponding z value is 1.96. This is determined from the normal distribution table.

We will apply the formula

Confidence interval

= mean +/- z ×standard deviation/√n

It becomes

0.903 +/- 1.96 × 0.0566/√6

= 0.903 +/- 1.96 × 0.0566/2.44948974278

= 0.903 +/- 0.045

The lower end of the confidence interval is 0.903 - 0.045 =0.858

The upper end of the confidence interval is 0.903 + 0.045 =0.948

Therefore, with 95% confidence interval, the mean lead concentration of the sea water is between 0.858 cc/cubic meter and 0.948 cc/cubic meter

You might be interested in

Jill's mother limited her xbox 1 playing to 10 hours per week. she played on only four days, a different amount of time each day

Brrunno [24]

You have to find out how much time she played on Saturday, Wednesday, Friday, and Sunday. Let's look at the facts.
Sunday: No info is given.
Friday: She played the least of all four days
Saturday: Twice as much as Wednesday
Wednesday: No info is given.

We can write a problem and solve from this information. Let's use the variable W for Wednesday. Saturday is 2W. So whatever number Wednesday has, multiply it by 2. All of the total numbers should equal 10.

Since Friday was played the least amount, we know that every other day has to be at least 2 hours or above, so that Friday can be 1 hour. Sunday we have no info given.

This is a bit of guess and see for this problem. Let's say that Friday was 1 hour, Wednesday was 2, Sunday was 3, and Saturday was 4. Total that equals 10. Let's check to varify that these numbers are correct.

Friday was the least amount of hours of any day, which is why it is 1.
Wednesday had 2 hours, and Saturday had twice that many, which is 4.
Sunday has 3 hours.

In short, your answer would be: Friday 1 hour, Wednesday 2 hours, Sunday 3 hours, and Saturday 4 hours. I hope I explained it wel

6 0

3 years ago

If F,G and H are midpoints of the sides of triangleCDE, FG=9, GH=7, and CD=24, find each measure

tensa zangetsu [6.8K]

Diagrams make explanations a lot easier so I created one, see bottom for the picture.

As GHF are all midpoints, that means the lines that connect them are half of the opposite sides.

CD = 2HF

DE = 2GF

CE = 2GH

As HF is 2x CD, and CD = 24:

HF = CD ÷ 2

HF = 24 ÷ 2 = 12

As DE = 2x GF and DF is 9:

DE = 2 x 9

DE = 18

As CE = 2x GH and GH = 7:

CE = 2 x 7

CE = 14

Hope this helps!

4 0

2 years ago

Evaluate the expression 4y^2 -a if x = 2, y = -3, and a =6

Vika [28.1K]

The expression is telling you to proceed as follows:

Pick some number $y$
Pick some number $a$
Compute the square of $y$
Multiply it by 4
Subtract $a$ from this result.

So, first of all, there's no point in fixing $x = 2$ , because x doesn't appear in the expression. As for the evaluation, let's follow the aforementioned steps with fixed values:

Pick some number $y$

Pick $y=-3$
Pick $a=6$
Compute $y^2 = (-3)^2 = 9$
Multiply it by 4: $9 \cdot 4 = 36$
Subtract $6$ from this result: $36-6=30$

3 0

3 years ago

50 points!!!!!!!

storchak [24]

Answer:1 and 1/3

Step-by-step explanation:

5 0

3 years ago

Find the value of n that makes DEF-XYZ when<br> DE = 4, EF = 5, XY = 4(n + 1). YZ = 7n - 1, and

oksano4ka [1.4K]

Answer: n=3

Step-by-step explanation:

Understand that you need to set up a proportion before you can try to solve the question through guessing. In this case, YZ would be proportional to XY as EF is proportional to DE. You would write this as: EF/DE=YZ/XY.

Now you want to write an equation. In order to do this remember to multiply by your proportion. Here’s my equation:

5/4(4n+4)=7n-1. Now distribute:

5n+5=7n-1. Now simplify:

6=2n. Now simplify again:

n=3

Hope this helps you with your big ideas math hw!

3 0

3 years ago