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
igor_vitrenko [27]
3 years ago
6

A boardwalk is to be erected along an ocean beach. The specifications for the boardwalk require a width of at least 155 cm., but

the pre-cut pieces of lumber supplied for the boardwalk are uniformly distributed in length between 148 cm. and 164 cm.
Mathematics
1 answer:
sleet_krkn [62]3 years ago
7 0

Answer:

a) X \sim Unif (a=148, b=164)

b) E(X) = \frac{a+b}{2}= \frac{148+164}{2}=156 cm

c) Var(X)= \frac{(b-a)^2}{12}= \frac{(164-148)^2}{12}= \frac{64}{3}= 21.33

Sd(X)= \sqrt{21.33}= 4.6188

d) P(X

e) P(155< X< 160)= F(160)-F(155)= \frac{160-148}{16} -\frac{155-148}{16}= 0.75-0.4375=0.3125Step-by-step explanation:

Assuming the following questions:

a. The distribution is X Use whole numbers.

Let X the random variable that represent the "lenght of pieces" used for the construction. We know that X follows an uniform distribution given by:

X \sim Unif (a=148, b=164)

b. The average length of the pieces of lumber is cm. Use whole numbers.

For this case the expected value for the distribution is given by:

E(X) = \frac{a+b}{2}= \frac{148+164}{2}=156 cm

c. Find the standard deviation.

First we need to calculate the variance given by:

Var(X)= \frac{(b-a)^2}{12}= \frac{(164-148)^2}{12}= \frac{64}{3}= 21.33

Sd(X)= \sqrt{21.33}= 4.6188

d. What's the probability that a randomly chosen piece of lumbar will be less than the required lenght?

For this case we can use the density function for X given by:

f(x) =\frac{1}{b-a}= \frac{1}{164-148}= \frac{1}{16} , 148 \leq X \leq 164

And the cumulative distribution function would be given by:

F(x) =\frac{x-148}{16} , 148 \leq X\leq 164

We want to find this probability:

P(X

e. Find the probability that a randomly chosen piece of lumber will be between 155 and 160 cm long?

For this case we want this probability:

P(155< X< 160)

And we can use the cdf function and we have:

P(155

You might be interested in
What is the slope of a line that is perpendicular to a line whose equation is -2y=3x+7? Help needed asap please :)
Alecsey [184]
I hope it helps you!!

6 0
2 years ago
Read 2 more answers
Order these weights from lightest to heaviest 10 ounces 1 pond and 1 ounce
Alchen [17]
1 ounce, 10 ounces, 1 pound.

1 pound = 16 ounces
6 0
3 years ago
I need some help with this:)I'll apreciate the answers.
Travka [436]
Part A: The discounted monthly fee is $22.49 (original cost of $29.99 multiplied by 75%, the amount the customer would pay since 25% is discounted.) Since you would also pay $44.99 for setup, your equation is $44.99+$22.49m Part B: Add 1.08 (108%; the customer pays 100% of the cost plus 8% more for tax) to your equation for the sales tax. 1.08(44.99+22.49m) Part C: Plug in 4 for m (m represents months). 1.08(44.99+22.49•4) 1.08(44.99+89.96) 1.08(134.95) $145.75 Hope that helps. Let me know if you need more assistance :)
7 0
3 years ago
ΔPQR has angle measurements of 80°, 50°, and 50°. What kind of triangle is ΔPQR?
sdas [7]

Answer:

isosceles

Step-by-step explanation:

as isosceles has two sides equal meaning two angles equal

6 0
2 years ago
Read 2 more answers
What is 1.7¯ expressed as a fraction in simplest form? <br> 13/7<br> 25/9<br> 8/7<br> 16/9
MissTica
<span> 1.7¯ (7 is repeating)

16/9 = 1.7777778

answer is 

16/9 
</span>
7 0
3 years ago
Read 2 more answers
Other questions:
  • If the sum of a number and 6 is multiplied by 5, the result is same as 9 times the number decreased by 2. find the number.
    14·1 answer
  • What is 3 + x/-2 = 10
    10·2 answers
  • A certain bacteria is growing at a rate of 4 percent each day. If the culture of bacteria has 5,000 bacteria today, how many bac
    6·2 answers
  • Please help! I will mark you as brainliest!
    5·2 answers
  • The stem-and-leaf plot shows the number of words in the classified ads in a newspaper one day.
    6·1 answer
  • Two factors of 20 add up to 6 what are they (I need full Explanation, Please)
    13·1 answer
  • Mrs. Lenz rented a scooter during her beach vacation. The cost of the scooter rental is shown for different periods of time. Wha
    7·1 answer
  • Jana wrote the expression 5n+3 as part of a problem she was solving. She wanted Sally to read it back to her verbally so she cou
    12·2 answers
  • Please help I don’t wanna add a bunch of points Bc nobody is helping me I’m just wasting them.
    15·1 answer
  • What is the value of the expression shown below?
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!