1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Vladimir79 [104]
3 years ago
13

A physicist examines 4 water samples for mercury concentration. The mean mercury concentration for the sample data is 0.470 cc/c

ubic meter with a standard deviation of 0.0581. Determine the 80% confidence interval for the population mean mercury 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.
Mathematics
1 answer:
Hitman42 [59]3 years ago
8 0

Answer:

Step-by-step explanation:

Answer:

Step-by-step explanation:

We want to determine a 80% confidence interval for the mean mercury concentration of water samples

Number of samples. n = 4

Mean or average = 0.470 cc/cubic meter

Standard deviation, s = 0.0581

For a confidence level of 80%, the corresponding z value is 1.28. This is determined from the normal distribution table.

We will apply the formula

Confidence interval

= mean +/- z ×standard deviation/√n

It becomes

0.470 +/- 1.28 × 0.0581/√4

= 0.470 +/- 1.28 × 0.0566/2

= 0.470 +/- 0.036

The lower end of the confidence interval is 0.470 - 0.036 =0.434

The upper end of the confidence interval is 0.470 + 0.036 =0.506

In conclusion, with a 80% confidence interval, the mean lead mean mercury concentration of the water samples is between 0.434 cc/cubic meter and 0.506 cc/cubic meter

You might be interested in
Easy question :)
bulgar [2K]
C. because 2.25 X 3 = 6.75 and 6.75 X 3 is 20.25
3 0
3 years ago
1. 5 less than one fourth of x is y.
horsena [70]

Answer

y = (1/4)x - 5                 or     4y - x + 20 = 0

Explanation

To get the rule required, we interpret the sentence and write it in a mathematical form.

5 less than one fourth of x is y  

one fourth of x ⇒ (1/4)x

5 less than one fourth of x is y  ⇒  (1/4)x - 5 = y

y = (1/4)x - 5

4y = x - 20

4y - x + 20 = 0

6 0
3 years ago
If f(x)=x^3-x, what is the average rate of change of f(x) over the interval [1,5]?
RSB [31]

Answer:

30

Step-by-step explanation:

Average rate of change=Δf(x)/Δx = [f(x2)-f(x1]/[x2-x1]

Δf(x)/Δx = [f(5)-f(1]/[5-1]

f(5)=5³-5=120

f(1)=1³-1=0

Δf(x)/Δx = [120-0]/[5-1]=120/4=30

4 0
3 years ago
Kate is a wage earner. One year she earned $72 000. She works 36 hours/week.
Lemur [1.5K]

Answer:

Kate's possible hourly rate of pay:  $34.75

Hours of overtime: 100

Step-by-step explanation:

In order to find Kate's hourly wage, we can set up an equation based on the number of hours she works per week and the estimated number of overtime hours to equal her total pay for the year.  If Kate works 36 hours/week and there are 52 weeks in a year, her total hours for one year are:  36 x 52 = 1872.  Setting up an equation based on her total earnings of $72,000:

1872x + 100(2x) = 72000, where 'x' is the hourly rate and '2x' is her overtime rate which is double time.

Combine like terms:  1872x + 200x = 72000 or 2072x = 72000

Divide both sides by 2072:  2072x/2072 = 72000/2072

Solve for x:  x = $34.75

Kate's hourly rate is estimated at $34.75.  We can check to see if this is correct by putting this value back into our original equation:

1872(34.75) + 100(2)(34.75) = 65052 + 6950 = 72002

The answer of $72,002 is very close to $72,000 and the best estimate of Kate's hourly wage and overtime hours.

8 0
3 years ago
The final cost of a sale item is determined by multiplying the price on the tag by 75%.which best describes the function that re
AnnZ [28]

Answer:

4V = 3U

Step-by-step explanation:

The final cost of a sale item is determined by multiplying the price on the tag by 75%.

Let us assume that the final cost of the sale item is V and the price on the tag is given by U.

Then the equation that best describes the function that represents the situation is V = \frac{75U}{100} =\frac{3U}{4}

⇒ 4V = 3U  (Answer)

3 0
3 years ago
Other questions:
  • Square root of 12 times negative 1 plus square root of 5
    12·1 answer
  • A school is looking to cater an event not having a food trick.food ​
    11·1 answer
  • -8 ( r + 6 ) = 7 ( r + 6 ) <br> solve the equation
    7·1 answer
  • The number of patients treated at Dr. White's dentist office each day for nine days is 10, 6, 4, 15, 6, 8, 6, 15, 4. Find the me
    10·1 answer
  • Hello people of the world whats 2+2
    13·2 answers
  • You start at (4, 5). You move down 9 units. Where do you end?
    5·2 answers
  • there are 10 students in a class 7 boys and 3 girls , what is the probability that everyone in the group is a boy
    10·2 answers
  • Clare earns 75 the next week from an after school job and deposits just enough into her account so that she is out of debt.
    15·1 answer
  • Determine the number of solution pairs in the equation.
    7·2 answers
  • Pythagorean Theorem
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!