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
olasank [31]
3 years ago
10

The area of a rhombus is given by the formula A=1/2xy,where x and y are the lengths of the diagonals. If the diagonals of a rhom

bus have lengths 10cm and 20cm, find the area of the rhombus.
Mathematics
1 answer:
Ivahew [28]3 years ago
3 0
The area of the triangle would be 100 cm
You might be interested in
I will give brainliest
Irina18 [472]

Answer: -3

Step-by-step explanation:

8 0
2 years ago
Let $$X_1, X_2, ...X_n$$ be uniformly distributed on the interval 0 to a. Recall that the maximum likelihood estimator of a is $
Solnce55 [7]

Answer:

a) \hat a = max(X_i)  

For this case the value for \hat a is always smaller than the value of a, assuming X_i \sim Unif[0,a] So then for this case it cannot be unbiased because an unbiased estimator satisfy this property:

E(a) - a= 0 and that's not our case.

b) E(\hat a) - a= \frac{na}{n+1} - a = \frac{na -an -a}{n+1}= \frac{-a}{n+1}

Since is a negative value we can conclude that underestimate the real value a.

\lim_{ n \to\infty} -\frac{1}{n+1}= 0

c) P(Y \leq y) = P(max(X_i) \leq y) = P(X_1 \leq y, X_2 \leq y, ..., X_n\leq y)

And assuming independence we have this:

P(Y \leq y) = P(X_1 \leq y) P(X_2 \leq y) .... P(X_n \leq y) = [P(X_1 \leq y)]^n = (\frac{y}{a})^n

f_Y (Y) = n (\frac{y}{a})^{n-1} * \frac{1}{a}= \frac{n}{a^n} y^{n-1} , y \in [0,a]

e) On this case we see that the estimator \hat a_1 is better than \hat a_2 and the reason why is because:

V(\hat a_1) > V(\hat a_2)

\frac{a^2}{3n}> \frac{a^2}{n(n+2)}

n(n+2) = n^2 + 2n > n +2n = 3n and that's satisfied for n>1.

Step-by-step explanation:

Part a

For this case we are assuming X_1, X_2 , ..., X_n \sim U(0,a)

And we are are ssuming the following estimator:

\hat a = max(X_i)  

For this case the value for \hat a is always smaller than the value of a, assuming X_i \sim Unif[0,a] So then for this case it cannot be unbiased because an unbiased estimator satisfy this property:

E(a) - a= 0 and that's not our case.

Part b

For this case we assume that the estimator is given by:

E(\hat a) = \frac{na}{n+1}

And using the definition of bias we have this:

E(\hat a) - a= \frac{na}{n+1} - a = \frac{na -an -a}{n+1}= \frac{-a}{n+1}

Since is a negative value we can conclude that underestimate the real value a.

And when we take the limit when n tend to infinity we got that the bias tend to 0.

\lim_{ n \to\infty} -\frac{1}{n+1}= 0

Part c

For this case we the followng random variable Y = max (X_i) and we can find the cumulative distribution function like this:

P(Y \leq y) = P(max(X_i) \leq y) = P(X_1 \leq y, X_2 \leq y, ..., X_n\leq y)

And assuming independence we have this:

P(Y \leq y) = P(X_1 \leq y) P(X_2 \leq y) .... P(X_n \leq y) = [P(X_1 \leq y)]^n = (\frac{y}{a})^n

Since all the random variables have the same distribution.  

Now we can find the density function derivating the distribution function like this:

f_Y (Y) = n (\frac{y}{a})^{n-1} * \frac{1}{a}= \frac{n}{a^n} y^{n-1} , y \in [0,a]

Now we can find the expected value for the random variable Y and we got this:

E(Y) = \int_{0}^a \frac{n}{a^n} y^n dy = \frac{n}{a^n} \frac{a^{n+1}}{n+1}= \frac{an}{n+1}

And the bias is given by:

E(Y)-a=\frac{an}{n+1} -a=\frac{an-an-a}{n+1}= -\frac{a}{n+1}

And again since the bias is not 0 we have a biased estimator.

Part e

For this case we have two estimators with the following variances:

V(\hat a_1) = \frac{a^2}{3n}

V(\hat a_2) = \frac{a^2}{n(n+2)}

On this case we see that the estimator \hat a_1 is better than \hat a_2 and the reason why is because:

V(\hat a_1) > V(\hat a_2)

\frac{a^2}{3n}> \frac{a^2}{n(n+2)}

n(n+2) = n^2 + 2n > n +2n = 3n and that's satisfied for n>1.

8 0
3 years ago
Help help help help help
e-lub [12.9K]

Answer: E: 100%

Step-by-step explanation:

If the class average is currently 70% and she wants to increase it by 10% every week for 3 weeks, 10×3=30% and 70+30= 100%.

PS- It would mean the world to me if you could mark me brainliest!

I am not a professional, I am simply using prior knowledge!

7 0
2 years ago
Choose the correct word(s) that completes each sentence. PLS HELP BEST GETS BRAINLESST​
dedylja [7]

Answer:

meter and then gallon

Step-by-step explanation:

i hope this helps :)

3 0
3 years ago
Read 2 more answers
Please help:<br> In Δ ABC, sin A= 77, sin C= 23, and c =16, find the length of A.
Dafna1 [17]

Answer:

39.9

Step-by-step explanation:

a/sinA = c/sinC

a/sin(77) = 16/sin(23)

a = sin(77) × 16/sin(23)

a = 39.89935764

3 0
2 years ago
Other questions:
  • I go to school on the 4th of June Monday and i summer term is on 29th June i have 3 days a week at school Monday Tuesday Wednesd
    11·1 answer
  • A dividing integers word problem
    6·1 answer
  • Can you please walk me step by step on how to do this I just need a bit of help you dont have to me the answers just and explana
    14·1 answer
  • Consider the equation |1/4+12|=x/2.Without calculating, how do you know x=-16 is an extraneous solution?
    11·1 answer
  • Complement of 70 degrees
    6·1 answer
  • Find an explicit formula for the geometric sequence <br> −8 ,−40 ,−200 ,−1000,...
    14·1 answer
  • If one person takes six hours to paint a house in another person takes 10 hours to paint house how long does it take them to pai
    8·1 answer
  • How do you write 21/30 as a percent?<br> Please show how to do it :D
    10·2 answers
  • Plz help i need some one to check if this is right :(
    13·1 answer
  • In ordered pair (x,y) ,x is called
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!