answer.
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
Orlov [11]
2 years ago
5

1. A farmer divided a field into 1-foot by 1-foot sections and tested soil samples from 32 randomly selected sections in the fie

ld. He finds that the mean pH level of the samples is 5.7 with a standard deviation of 0.26.
A. Find the mean and standard deviation of the sampling distribution of all possible soil samples of size n = 32. Round to three decimal places.
B. Construct a 95% confidence interval for the mean pH level of soil samples from every 1-foot by 1-foot section. Show your work. Even if you use technology, show the expression that is used to determine the margin of error for the interval. Interpret the interval in a complete sentence.
C. The farmer tested soil samples from 34 randomly selected sections from another field. He found
the mean pH level of those samples to be 6.1 with a standard deviation of 0.34. Construct a 95% confidence interval for the difference between the mean pH levels of all possible soil samples from both fields. Show your work. Even if you use technology, show the expression that is used to determine the margin of error for the interval. Interpret the interval in a complete sentence.
Answer:
Mathematics
1 answer:
Ad libitum [116K]2 years ago
5 0
Part A

Answers:
Mean = 5.7
Standard Deviation = 0.046

-----------------------

The mean is given to us, which was 5.7, so there's no need to do any work there.

To get the standard deviation of the sample distribution, we divide the given standard deviation s = 0.26 by the square root of the sample size n = 32
So, we get s/sqrt(n) = 0.26/sqrt(32) = 0.0459619 which rounds to 0.046

================================================

Part B

The 95% confidence interval is roughly (3.73, 7.67)
The margin of error expression is z*s/sqrt(n)
The interpretation is that if we generated 100 confidence intervals, then roughly 95% of them will have the mean between 3.73 and 7.67

-----------------------

At 95% confidence, the critical value is z = 1.96 approximately

ME = margin of error
ME = z*s/sqrt(n)
ME = 1.96*5.7/sqrt(32)
ME = 1.974949
The margin of error is roughly 1.974949

The lower and upper boundaries (L and U respectively) are:
L = xbar-ME
L = 5.7-1.974949
L = 3.725051
L = 3.73
and
U = xbar+ME
U = 5.7+1.974949
U = 7.674949
U = 7.67

================================================

Part C

Confidence interval is (5.99, 6.21)
Margin of Error expression is z*s/sqrt(n)
If we generate 100 intervals, then roughly 95 of them will have the mean between 5.99 and 6.21. We are 95% confident that the mean is between those values.

-----------------------

At 95% confidence, the critical value is z = 1.96 approximately

ME = margin of error
ME = z*s/sqrt(n)
ME = 1.96*0.34/sqrt(34)
ME = 0.114286657
The margin of error is roughly 0.114286657

L = lower limit
L = xbar-ME
L = 6.1-0.114286657
L = 5.985713343
L = 5.99

U = upper limit
U = xbar+ME
U = 6.1+0.114286657
U = 6.214286657
U = 6.21
You might be interested in
Assume that z scores are normally distributed with a mean of 0 and a standard deviation of 1. if p(z >
madreJ [45]
Given that μ=0, and σ=1, P(z>c)=0.1093
thus
P(z<c)=1-0.1093=0.8907
hence the value of c will be:
z-score=(c-μ)/σ
thus
1.23=(c-0)/1
c=1.23
8 0
2 years ago
A recent article in Business Week listed the "Best Small Companies." We are interested in the current results of the companies'
Sindrei [870]

Answer:

(i) The estimated regression equation is;

\hat y ≈ 1.6896 + 0.0604·X

The coefficient of 'X' indicates that \hat y increase by a multiple of 0.0604 for each million dollar increase in sales, X

(ii) The estimated earnings for the company is approximately $4.7096 million

(iii) The standard error of estimate is approximately 29.34

The high standard error of estimate indicates that individual mean do not accurately represent the population mean

(iv) The coefficient of determination is approximately 0.57925

The coefficient of determination indicates that the probability of the coordinate of a new point of data to be located on the line is 0.57925

Step-by-step explanation:

The given data is presented as follows;

\begin{array}{ccc}Sales \ (\$million)&&Earning \ (\$million) \\89.2&&4.9\\18.6&&4.4\\18.2&&1.3\\71.7&&8\\58.6&&6.6\\46.8&&4.1\\17.5&&2.6\\11.9&&1.7\end{array}

(i) From the data, we have;

The regression equation can be presented as follows;

\hat y = b₀ + b₁·x

Where;

b₁ = The slope given as follows;

b_1 = \dfrac{\Sigma(x_i - \overline x) \cdot (y_i - \overline y)}{\Sigma(x_i - \overline x)^2}

b₀ = \overline y - b₁·\overline x

From the data, we have;

{\Sigma(x_i - \overline x) \cdot (y_i - \overline y)} = 364.05

\Sigma(x_i - \overline x)^2} = 6,027.259

\overline y = 4.2

\overline x = 41.5625

∴ b₁ = 364.05/6,027.259 ≈ 0.06040059005

b₀ = 4.2 - 0.06040059005 × 41.5625 ≈ 1.68960047605 ≈ 1.69

Therefore, we have the regression equation as follows;

\hat y ≈ 1.6896 + 0.0604·X

The coefficient of 'X' indicates that the earnings increase by a multiple of 0.0604 for each million dollar increase in sales

(ii) For the small company, we have;

X = $50.0 million, therefore, we get;

\hat y = 1.6896 + 0.0604 × 50 = 4.7096

The estimated earnings for the company, \hat y = 4.7096 million

(iii) The standard error of estimate, σ, is given by the following formula;

\sigma =\sqrt{\dfrac{\sum \left (x_i-\mu  \right )^{2} }{n - 1}}

Where;

n = The sample size

Therefore, we have;

\sigma =\sqrt{\dfrac{6,027.259 }{8 - 1}} \approx 29.34

The standard error of estimate, σ ≈ 29.34

The high standard error of estimate indicates that it is very unlikely that a given mean value within the data is a representation of the true population mean

(iv) The coefficient of determination (R Square) is given as follows;

R^2 = \dfrac{SSR}{SST}

Where;

SSR = The Sum of Squared Regression ≈ 21.9884

SST = The total variation in the sample ≈ 37.96

Therefore, R² ≈ 21.9884/37.96 ≈ 0.57925

The coefficient of determination, R² ≈ 0.57925.

Therefore, by the coefficient of determination, the likelihood of a new introduced data point to located on the line is 0.57925

6 0
2 years ago
A pendulum's first swing has an arc of 24 inches. As the pendulum swings back and forth, the arc length for each successive swin
andrezito [222]

Answer:

4

Step-by-step explanation:

8 0
2 years ago
Read 2 more answers
A particular convex pentagon has two congruent, acute angles. The measure of each of the other interior angles is equal to the s
NNADVOKAT [17]

1. First, you must apply the formula for calculate the sum of the interior angles of a regular polygon, which is shown below:


 (n-2) × 180°


 "n" is the number of sides of the polygon (n=5).


 2. Then, the sum of the interior angles of the pentagon, is:


 (5-2)x180°=540°


 3. The problem says that the measure of each of the other interior angles is equal to the sum of the measures of the two acute angles and now you know that the sum of all the angles is 540°, then, you have:


 α+α+2α+2α+2α=540°

 8α=540°

 α=540°/8

 α=67.5°


 4. Finally, the larger angle is:


 2α=2(67.5°)=135°


 5. Therefore, the answer is: 135°

6 0
2 years ago
A dolphin is 42 feet underwater and ascends at a constant rate for 14 seconds until it reaches the surface. Identify and interpr
Cloud [144]
Ok so, based on the graph lets say that x = seconds and  y = depth of dolphin. the interception in both points is when they are at 0 i.e when x is equals 0 and y equals 0. So At 0 seconds, the dolphin is 42 feet below the surface. So we say that x = 0, y = -42 and then the y intercepts = -42 so the point of interception is(0 (seconds),-42(depth of the dolphin)) When the clock says it's 14 seconds, the dolphin is even with the surface (0 below the surface this time). So we say that x = 14, y = 0. In this case The x intercept = 14 (14,0). But we need to calculate The slope with the formula= (y2 - y1)/(x2 - x1) = 42/14 = 3. Therefore, the formula for this line is y = 3x - 42.
3 0
2 years ago
Other questions:
  • Find the surface area of a triangular prism that has the following dimensions. Use the formula SA = 2 B + Ph . B = 84 mm 2 P = 5
    10·1 answer
  • Bella spent 15% of her paycheck at the mall, and 40% of that was spent at the movie theater. Bella spent a total of $13.74 at th
    14·1 answer
  • PLS HELP ME ASAP Amy must form a three-letter arrangement using only letters from the word dice. She cannot use a letter more th
    15·2 answers
  • Tommy is ordering concrete for a construction project. The price of concrete is $.02 per pound. Concrete is also taxed at a rate
    10·1 answer
  • The total load on a certain service is 525 kVA. One-third of this load is from motors; 3/5 is lighting; and 1/15 is from other l
    15·1 answer
  • Suppose the Sunglasses Hut Company has a profit function given by P ( q ) = − 0.02 q 2 + 5 q − 30 , where q is the number of tho
    8·1 answer
  • Suppose, instead, that Bruce used 6 full boxes of tiles plus an additional 2 tiles, and Felicia used 5 full boxes of tiles plus
    14·2 answers
  • Which is the solution of the quadratic equation (4y – 3)2 = 72? y = StartFraction 3 + 6 StartRoot 2 EndRoot Over 4 EndFraction a
    8·2 answers
  • There are between 60 and 100 children at the sunny side holiday camp. When the children are put into pairs, there is 1 child lef
    15·1 answer
  • A researcher takes a random sample of 2,496 drivers and finds that 1,603 put their phone in "drive mode” to not be distracted wh
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!