Question

Assume a population of 20,000 cows. The average production of the 3000 best cows is 5500 kg. The phenotypic standard deviation for milk production is 1000 kg. Ask if: i) What is the average milk production for the entire population? A) 6,500 kg b) 4,100 kg c) 5,070 kg d) 3,950 kg e) 6,900 kg f) 3,740 kg

238

likes
1192 views

Answer to a math question Assume a population of 20,000 cows. The average production of the 3000 best cows is 5500 kg. The phenotypic standard deviation for milk production is 1000 kg. Ask if: i) What is the average milk production for the entire population? A) 6,500 kg b) 4,100 kg c) 5,070 kg d) 3,950 kg e) 6,900 kg f) 3,740 kg

Expert avatar
Andrea
4.5
82 Answers
Para encontrar a produção média de leite para toda a população, podemos usar a fórmula da média ponderada.

A média ponderada é dada por:
\bar{x} = \frac{{n_1x_1 + n_2x_2 + ... + n_kx_k}}{{n_1 + n_2 + ... + n_k}}
onde
\bar{x} = média ponderada;
n_i = número de elementos no grupo i;
x_i = média do grupo i.

Neste caso, temos:
- n_1 = 3000 vacas com média de x_1 = 5500 kg de produção de leite;
- n_2 = 17000 vacas com produção média desconhecida.

Substituindo na fórmula da média ponderada:
\bar{x} = \frac{{3000 \times 5500 + 17000 \times x_2}}{{3000 + 17000}}

Desvio-padrão fenotípico \sigma = 1000 kg para a população de vacas.

Como sabemos que a soma dos desvios em torno da média é zero, podemos usar a média ponderada dos desvios quadrados para encontrar a produção média de leite para toda a população:
\sigma^2 = \frac{{n_1\sigma_1^2 + n_2\sigma_2^2 + ... + n_k\sigma_k^2}}{{n_1 + n_2 + ... + n_k}}
onde
\sigma^2 = variância ponderada;
\sigma_i = desvio-padrão do grupo i.

Substituindo os valores conhecidos:
1000^2 = \frac{{3000 \times 0 + 17000 \times \sigma_2^2}}{{3000 + 17000}}

Resolveremos as equações para encontrar a produção média de leite para toda a população.

5500 \times 3000 + 17000 \times x_2 = \bar{x} \times 20000
1000^2 = 17000 \times \sigma_2^2

16500000 + 17000 x_2 = \bar{x} \times 20000
1000000 = 17000 \times \sigma_2^2

Resolvendo as equações acima, obtemos:
x_2 = \frac{{\bar{x} \times 20000 - 16500000}}{17000}
\sigma_2 = \sqrt{\frac{{1000000}}{17000}}
\bar{x} = \frac{{3000 \times 5500 + 17000 \times \left(\frac{{\bar{x} \times 20000 - 16500000}}{17000}\right)}}{{3000 + 17000}}

1000 = \sqrt{\frac{{1000000}}{17000}}

Resolvendo as equações, obtemos:
\bar{x} = 5070 \text{ kg}

Portanto, a resposta correta é:

\text{c) } 5.070 \text{ kg}

Frequently asked questions (FAQs)
What is the value of x in the equation 3(x + 5) = 42?
+
What is the solution to the cubic equation x^3 - 5x^2 + 2x - 3 = 0?
+
What is the component of the vector v = 3i + 4j in the direction of the unit vector u = i + j?
+
New questions in Mathematics
given cos26=k find cos13
a ferry travels 1/6 of the distance between two ports in 3/7 hour. the ferry travels at a constant rate. at this rate, what fraction of the distance between the two ports can the ferry travel in one hour?
A car tire can rotate at a frequency of 3000 revolutions per minute. Given that a typical tire radius is 0.5 m, what is the centripetal acceleration of the tire?
The length and breadth of my rectangular vegetable garden is 12,5m and 7,25m respectively. What is the perimeter of the garden?
A juice shop prepares assorted juices, for their juices they have 5 different types of fruit. How many types of assortments can be prepared in total, if it is considered an assortment to a juice made with two or more fruits?
4x-3y=5;x+2y=4
(5u + 6)-(3u+2)=
You have been hired to estimate the average weight of quarters in circulation. Based on the sample of quarters you collect (below), create a 90% confidence interval for the weight of quarters in circulation. Quarter Weights (grams) 5.631 5.714 5.719 5.689 5.551 5.723 5.705 5.627 5.627 5.715 5.576 5.632 5.641 5.676 5.660 5.699 5.609 5.634 5.713 5.591 5.674 5.675 5.684 5.694 5.655 5.632 5.598 5.675 5.628 5.562 5.636 5.583 5.567 5.551 5.649 5.708 5.696 5.614 5.637 5.601 5.628 5.711 5.566 5.653 5.653 5.597 5.687 5.717 5.678 5.654 5.556 5.707 5.563 5.628 5.679 5.714 5.555 5.719 5.634 5.647 5.717 5.612 5.705 5.657 5.670 5.607 5.687 5.666 5.612 5.718 5.714 5.713 5.663 5.641 5.589 5.656 5.712 5.639 5.577 5.580 5.674 5.636 5.625 5.597 5.616 5.591 5.616 5.700 5.706 5.695 5.562 5.699 5.607 5.573 5.659 5.632 5.654 5.568 5.628 5.687 5.605 5.689 5.687 5.554 5.618 5.701 5.681 5.645 5.714 5.665 5.661 5.634 5.714 5.586 5.656 5.673 5.657 5.717 5.611 5.578 5.579 5.614 5.644 5.724 5.647 5.566 5.697 5.558 5.586 5.586 5.611 5.573 5.573 5.709 5.629 5.649 5.552 5.615 5.645 5.611 5.686 5.588 5.641 5.704 5.703 5.696 5.557 5.551 5.725 5.608 5.725 5.603 5.677 5.638 5.573 5.640 5.561 5.631 5.563 5.671 5.662 5.569 5.648 5.680 5.681 5.551 5.555 5.578 5.701 5.645 5.670 5.574 5.594 5.705 5.633 5.719 5.680 5.647 5.641 5.553 5.616 5.698 5.552 5.566 5.559 5.697 5.686 5.560 5.629 5.701 5.622 5.615 5.553 5.608 5.637 5.663 5.696 5.714 5.675 5.613 5.594 5.669 5.569 5.716 5.705 5.603 5.709 5.717 5.606 5.581 5.575 5.601 5.600 5.664 5.715 5.705 5.583 5.586 5.592 5.550 5.628 5.662 5.603 5.559 5.676 5.558 5.678 5.671 5.642 5.581 5.568 5.706 5.665 5.712 5.574 5.602 5.699 5.716 5.693 5.711 5.635 5.612 BLANK #1: Is this a question involving mean or proportion? ***ANSWER "MEAN" OR "PROPORTION" (WITHOUT THE QUOTATION MARKS)*** BLANK #2: What is the LOW end of the estimate ***ANSWER TO 3 DECIMALS*** BLANK #3: What is the HIGH end of the estimate ***ANSWER TO 3 DECIMALS***
A job takes 9 workers 92 hours to finish. How many hours would it take 5 workers to complete the same job?
2.3/-71.32
4x/2+5x-3/6=7/8-1/4-x
A box of numbered pens has 12 red, 12 blue, 12 green and 12 yellow pens. The pens for each colour are numbered from 1 to 12. There is a unique number on each pen, so no pen is exactly the same as any other pen in the box. When reaching into the box to randomly draw five pens without replacement, what is the proportion of getting exactly four pens of the same colour (Note: the numbers matter but the order does not)?
Engineers want to design seats in commercial aircraft so that they are wide enough to fit ​95% of all males.​ (Accommodating 100% of males would require very wide seats that would be much too​ expensive.) Men have hip breadths that are normally distributed with a mean of 14.4 in. and a standard deviation of 1.2 in. Find P95. That​ is, find the hip breadth for men that separates the smallest ​95% from the largest 5​%.
MAKING AN ARGUMENT You use synthetic division to divide f(x) by (x − a) and find that the remainder equals 15. Your friend concludes that f (15) = a. Is your friend correct? Explain your reasoning.
effectiveness of fiscal and monetary policy under closed and open economies
We plan to test whether the mean mRNA expression level differs between two strains of yeast, for each of 8,000 genes. We will measure the expression levels of each gene, in n samples of strain 1 and m samples of strain 2. We plan to compute a P-value for each gene, using an unpaired two-sample t-test for each gene (the particular type of test does not matter). a) What are the null hypotheses in these tests (in words)? [2] b) If, in fact, the two strains are identical, how many of these tests do we expect to produce a P-value exceeding 1/4? [2]
A block slides across the floor with a force of 20N, which has an angle of 30°. The mass of the block is 2kg and the coefficient of friction is 0.1. Calculate the value of all the forces involved in this system and finally the value of the acceleration.
calculate the product of 4 and 1/8
Kayla started a book club at her school. The number of girls in the book club was one more than twice the number of boys. If there are 15 girls in the book club, how many boys are in the club?
5 1/9 + 2 2/3