2.7.2 : Checkup - Practice Problems
A service station has both self-service and full-service islands. On each island, there is a single regular unleaded pump with two hoses. Let X denote the number of hoses being used on the self-service island at a particular time, and let Y denote the number of hoses on the full-service island in use at that time. The joint pmf of X and Y appears in the accompanying tabulation.
Y
p(x,y) 0 1 2
x 0 0.10 0.04 0.02
1 0.08 0.20 0.06
2 0.06 0.14 0.30
a. What is P(X = 1 and Y = 1)?
b. Compute P(X ≤ 1 and Y ≤ 1).
c. Give a word description of the event {X ≠ 0 and Y ≠ 0}, and compute the probability of this event.
d. Compute the marginal pmf of X and of Y. Using pX(x), what is P(X ≤ 1)?
e. Are X and Y independent rv’s? Explain.
Answer:
a. 0.2
b. 0.42
c. 0.7
d. the solution is in the explanation
e. x and y are not independent
Step-by-step explanation:
a. from the joint probability mass function table,
p(x=1) and p(Y= 1)
= p(1,1) = 0.2
b. prob(0,0)+prob(0,1)+prob(1,0)+prob(1,1)
= 0.10 + 0.04 + 0.08 + 0.20
= 0.42
P(X ≤ 1 and Y ≤ 1) = 0.42
c. prob {X ≠ 0 and Y ≠ 0}
= prob(1,1) + prob(1,2) + prob(2,1) + prob(2,2)
= 0.20 + 0.06 + 0.14 + 0.30
= 0.7
d. we have to calculate the marginal pmf of x and y here.
we have the x values as 0,1,2
prob(x=0) = 0.1 + 0.04 + 0.02
= 0.16
prob(x=1) = 0.08 + 0.2 + 0.06
= 0.34
prob(x=2) = 0.06+0.14+0.3
= 0.50
we have y values as 0,1,2
prob(y=0) = .1+.08+.06
= 0.24
prob(y=1) = .04+.2+.14
= 0.38
prob(y = 2) = 0.02+0.06+0.3
= 0.38
P(X ≤ 1) = prob(x=0)+prob(x=1)
= 0.34+0.16
= 0.50
e. from the joint table we have this,
prob(1,1) = 0.2
prob(x=1) = 0.34
prob(y=1) = 0.38
then prob(x=1)*prob(y=1)
= 0.34*0.38
= 0.1292
therefore prob(1,1) is not equal to prob(x=1)*prob(y=1)
0.2≠0.1292
x and y are not independent
Matthew participates in a study that is looking at how confident students at SUNY Albany are. The mean score on the scale is 50. The distribution has a standard deviation of 10 and is normally distributed. Matthew scores a 65. What percentage of people could be expected to score the same as Matthew or higher on this scale
Answer:
The percentage of people that could be expected to score the same as Matthew or higher on this scale is:
= 93.3%.
Step-by-step explanation:
a) Data and Calculations:
Mean score on the scale, μ = 50
Distribution's standard deviation, σ = 10
Matthew scores, x = 65
Calculating the Z-score:
Z-score = (x – μ) / σ
= (65-50)/10
= 1.5
The probability based on a Z-score of 1.5 is 0.93319
Therefore, the percentage of people that could be expected to score the same as Matthew or higher on this scale is 93.3%.
After a 13% price reduction, a boat sold for $25,230. What was the boat's price before the reduction? (Round to the nearest cent, if necessary.) Group of answer choices
Answer:
The boat's price before the reduction was $ 29,000.
Step-by-step explanation:
Given that after a 13% price reduction, a boat sold for $ 25,230, to determine what was the boat's price before the reduction, the following calculation must be performed:
100 - 13 = 87
87 = 25230
100 = X
100 x 25 230/87 = X
2523000/87 = X
29000 = X
Therefore, the boat's price before the reduction was $ 29,000.
Golf Scores In a professional golf tournament the players participate in four rounds of golf and the player with the lowest score after all four rounds is the champion. How well does a player's performance in the first round of the tournament predict the final score
Answer:
Mean scores.
Step-by-step explanation:
The golf player will score in the first round, according to these scores the golf player scores can be predicted. The golf player can perform high in first round but he may score lesser in the second round due to stress or mental pressure. The scores can be predicted taking mean of the scores and adding standard deviation to it.
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Two cyclists, 68 miles apart, start riding toward each other at the same time. One cycles 3 miles per hour faster than the other, and they meet after 4 hours of riding.
a. Write an equation using the information as it is given above that can be solved to answer this problem.
Use the variable r to represent the speed of the slower cyclist. b. What are the speeds of the two cyclists? _______________
Answer:
4r + 4(r + 3) = 68
r = 7 miles per hour
r + 3 = 10 miles per hour
Step-by-step explanation:
distance = rate * time
a)
4r + 4(r + 3) = 68
Distribute
4r + 4r + 12 = 68
8r + 12 = 68
8r = 56
r = 7 miles per hour
r + 3 = 10 miles per hour
Will give brainliest answer
Answer:
Below.
Step-by-step explanation:
log 10 ( 100 ) = 2
Answer:
First one: log_10 (100) = 2 OR log (100) = 2
Second one: 5^-3 = 1/125
Step-by-step explanation:
Let's say the formula for a basic exponent equation is this:
a = b^x
a is the answer when you calculate b^x
b is the base
x is the exponent
Here's the log formula using those variables:
log_b (a) = x
As long as you know how to rearrange the numbers/variables, you are good to go:
100 = 10^2
a = 100
b = 10
x = 2
log_10 (100) = 2
You can also write this one as log (100) = 2 because when you put log by itself, it's assumed that the base thing already equals 10.
log_5 (1/125) = -3
a = 1/125
b = 5
x = -3
5^-3 = 1/125
Hope it helps (●'◡'●)
A sample of 1300 computer chips revealed that 50% of the chips do not fail in the first 1000 hours of their use. The company's promotional literature claimed that more than 47% do not fail in the first 1000 hours of their use. Is there sufficient evidence at the 0.05 level to support the company's claim
Answer:
The p-value of the test is 0.015 < 0.05, which means that there is sufficient evidence at the 0.05 level to support the company's claim.
Step-by-step explanation:
The company's promotional literature claimed that more than 47% do not fail in the first 1000 hours of their use.
At the null hypothesis, we test if the proportion is of 47% or less, that is:
[tex]H_0: p \leq 0.47[/tex]
At the alternative hypothesis, we test if the proportion is of more than 47%, that is:
[tex]H_1: p > 0.47[/tex]
The test statistic is:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.
0.47 is tested at the null hypothesis:
This means that [tex]\mu = 0.47, \sigma = \sqrt{0.47*0.53}[/tex]
A sample of 1300 computer chips revealed that 50% of the chips do not fail in the first 1000 hours of their use.
This means that [tex]n = 1300, X = 0.5[/tex]
Value of the statistic:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
[tex]z = \frac{0.5 - 0.47}{\frac{\sqrt{0.47*0.53}}{\sqrt{1300}}}[/tex]
[tex]z = 2.17[/tex]
P-value of the test and decision:
The p-value of the test is the probability of finding a sample proportion above 0.5, which is 1 subtracted by the p-value of z = 2.17.
Looking at the z-table, z = 2.17 has a p-value of 0.9850
1 - 0.985 = 0.015
The p-value of the test is 0.015 < 0.05, which means that there is sufficient evidence at the 0.05 level to support the company's claim.
Which of the following shows the graph of y = 4^x + 3?
The images of the graphs are missing and so i have attached them.
Answer:
Graph in option A
Step-by-step explanation:
y = 4^(x) + 3
Let's input some values of x and find the corresponding value of y and see if any of the graph matches the coordinates we get.
At x = 0;
y = 4^(0) + 3
y = 4
At x = 1;
y = 4^(1) + 3
y = 7
At x = 2;
y = 4^(2) + 3
y = 19
Looking at all the graphs, the only one with y = 4 when x = 0 is graph A
Let T be the event that an adult admits to texting while driving and N be the event an adult does not admit to texting while driving. We previously determined
P(T) = 0.61
and
P(N) = 0.39.
Since three adults are chosen randomly, we have the following simple events.
TTT TTN TNT NTT TNN NTN NNT NNN
The adults were randomly selected, indicating these can be seen as independent events. Therefore, the multiplication rule can be used. Recall the multiplication rule states that for independent events, the probability that they all occur is the product of their respective probabilities. Let x be the number of adults who admit to texting while driving. Since three adults are randomly selected, then x can take on the values 0, 1, 2, or 3.
When x = 0, then no adult in the group of three admits to texting while driving. This corresponds to the simple event NNN whose probability is calculated as below.
P(x = 0) = P(NNN)
= P(N)P(N)P(N)
= 0.39(0.39)(0.39)
=
When x = 1, then only one adult in the group admits to texting while driving. This corresponds to the simple events TNN, NTN, and NNT. First, calculate the probability of each simple event by multiplying the individual probabilities. Then sum the three simple events to find
P(x = 1).
Calculate
P(x = 1).
P(x = 1) = P(TNN) + P(NTN) + P(NNT)
= P(T)P(N)P(N) + P(N)P(T)P(N) + P(N)P(N)P(T)
= 0.61(0.39)(0.39) + 0.39(0.61)(0.39) + 0.39(0.39)(0.61)
=
Find the remaining probabilities
P(x = 2)
and
P(x = 3).
P(x = 2) = P(TTN) + P(TNT) + P(NTT)
= P(T)P(T)P(N) + P(T)P(N)P(T) + P(N)P(T)P(T)
= 0.61(0.61)(0.39) + 0.61(0.39)(0.61) + 0.39(0.61)(0.61)
=
P(x = 3) = P(TTT)
= P(T)P(T)P(T)
= 0.61(0.61)(0.61)
=
Answer:
Step-by-step explanation:
X P(X=x)
0 0.39*0.39*0.39 = 0.059319
1 3*0.61*0.39*0.39 = 0.278343
2 3*0.61*0.61*0.39 = 0.435357
3 0.61*0.61*0.61 = 0.226981
Find domain of (x^2+3)+[tex]\sqrt{x} 3x-1[/tex]
Answer:
= x^2 + 3 + √3x^2 - 1
Step-by-step explanation:
Remove parentheses: (a) = a
= x^2 + 3 + √x . 3x - 1
x . 3x = 3x^2
= x^2 + 3 + √3x^2 - 1
I WILL GIVE BRAINLIEST FAST
Answer:
is opposite line BC. Answer is letter E.
The sum of the angles of a triangle is 180. Find the three angles if one angle is twice the smallest angle and the third angle is 36 degrees greater than the smallest angle. Place them in order from least to greatest.
Answer:
36°, 72°, 72°Step-by-step explanation:
The angles are x, y and z:
x = 2y, z = y + 36Their sum is:
x + y + z = 1802y + y + y + 36 = 1804y = 144y = 36Then find the other angles:
x = 2*36 = 72z = 36 + 36 = 72Now we have to,
find the three angles if one angle is twice smallest angle and third angle is 36° greater than smallest angle.
Then take the values as,
→ smallest angle = x
→ y = 2x
→ z = x + 36°
Let we find the angles,
→ x + y + z = 180°
→ x + 2x + x + 36° = 180°
→ 4x = 180 - 36
→ 4x = 144
→ x = 144/4
→ [x = 36°]
Now the value of y is,
→ y = 2x
→ y = 2 × 36°
→ [y = 72°]
Then the value of z is,
→ z = x + 36°
→ z = 36° + 36°
→ [z = 72°]
Placing values from least to greatest,
→ 36°, 72°, 72°
Hence, the order is 36°, 72°, 72°.
Which expression gives the best estimate of 30 percent of 61?
The answers are below:
Hurry, please!
Answer:
it would be 1/4(60)
Step-by-step explanation:
30 percent of 61 is 18.3 and 1/4 of 60 is 15 which is closest to 18.3
Side CA of the right triangle CAT is 3cm long. The hypotenuse is 5cm long. How many
square centimeters is the area of CAT?
Answer:
8
Step-by-step explanation:
By taking the number "3" and plus together with the number 5
Directions: Find each missing measure
Answer:
Q9: x = 27, Q10: x = 17
Step-by-step explanation:
stuck on this problem
Answer:
B
Step-by-step explanation:
When we reflect something across the y axis, the y axis stays the same but the x values change by a factor of -1.
B is the Answer
Answer:
c. switch the x-values and y-values in the table
Step-by-step explanation:
For any table or graph reflection over the line y=x
The rule is (x,y) ----> (y,x)
f(x) is reflected over the line y=x, so the coordinates of f(x) becomes
(-2,-31) becomes (-31,-2)
(-1,0) becomes (0,-1)
(1,2) becomes (2,1)
(2,33) becomes (33,2)
As per the rule, we switch the x-values and y-values in the table
For reflection over the line y=x , the coordinate becomes
(-31,-2)
(0,-1)
(2,1)
(33,2)
2.According to www.city-data, the mean price for a detached house in Franklin County, OH in 2009 was $192,723. Suppose we know that the standard deviation was $42,000. Check the three assumptions associated with the Central Limit Theorem. What is the probability that a random sample of 75 detached houses in Franklin County had a mean price greater than $190,000 in 2009
Answer:
0.7123 = 71.23% probability that a random sample of 75 detached houses in Franklin County had a mean price greater than $190,000 in 2009.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
The mean price for a detached house in Franklin County, OH in 2009 was $192,723. Suppose we know that the standard deviation was $42,000.
This means that [tex]\mu = 192723, \sigma = 42000[/tex]
Sample of 75:
This means that [tex]n = 75, s = \frac{42000}{\sqrt{75}}[/tex]
What is the probability that a random sample of 75 detached houses in Franklin County had a mean price greater than $190,000 in 2009?
1 subtracted by the p-value of Z when X = 190000. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{190000 - 192723}{\frac{42000}{\sqrt{75}}}[/tex]
[tex]Z = -0.56[/tex]
[tex]Z = -0.56[/tex] has a p-value of 0.2877
1 - 0.2877 = 0.7123
0.7123 = 71.23% probability that a random sample of 75 detached houses in Franklin County had a mean price greater than $190,000 in 2009.
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How many triangles are there in this picture?
Im sorry if you get this wrong but im going with 14 only because i did this question with my class in school and a boy said 14 and got it right.
Answer:
28
Step-by-step explanation:
there are bigger triangles in the triangles pls dont remove
Jason planted and staked a tree. The stakes are 21 ft from the base of the tree. They are connected to wires that attach to the trunk at a height of 20 ft. Find the length of a wire.
14 ft
15 ft
20 ft
29 ft
Based on the height that the wires attach, and the base length of the stakes, the length of the wire is 29 ft.
How long are the wires?This can be solved with the Pythagorean theorem because the height can be treated as the height of a right-angled triangle. The base as the base of the triangle.
The length of the wire is the hypothenuse.
Length:
c² = a² + b²
c² = 21² + 20²
c² = 841
c = √841
= 29 ft
Find out more on the Pythagorean theorem at https://brainly.com/question/343682.
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Suppose y varies inversely with X, and y = 36 when x = 1/12. What inverse variation equation relates x and y?
NO LINKS OR ANSWERING YOU DON'T KNOW!!!
a. y= 3x
b. y= 3/x
c. x/3
d. y= x
Answer:
B
Step-by-step explanation:
We are given that y varies inversely with x. Recall that inverse variation has the form:
[tex]\displaystyle y=\frac{k}{x}[/tex]
Where k is the constant of variation.
We are given that y = 36 when x = 1/12. Thus:
[tex]\displaystyle (36)=\frac{k}{\left({}^{1}\!/\!{}_{12}\right)}[/tex]
Solve for k. Multiply both sides by 1/12:
[tex]\displaystyle k=\frac{1}{12}(36)=3[/tex]
Hence, our equation is:
[tex]\displaystyle y=\frac{3}{x}[/tex]
Our answer is B.
what is the value of x
Write a rational function that meets the following criteria:
Vertical asymptote at x = 1
Horizontal asymptote at y = 2
and a hole at x = 3
Find the value of x in each case:
Answer:
36
Step-by-step explanation:
2x is an exterior angle
Exterior angles = the sum of the two remote (unconnected - non supplementary interior angles).
Put symbolically
<LEG = <EGF + <EFG
<EFG = 180 - 4x In this case you need to find the supplemtnt
<LEG = x + 180 - 4x
2x = 180 - 3x Add 3x to both sides
5x = 180 Divide by 5
x = 36
A few years ago, people tended to have relatively large CD collections. For students at a large university in the midwest, the mean number of CDs owned was 78 with a standard deviation of 90. To confirm these numbers, a random sample of 120 students from this university was collected and the size of their CD collections recorded. These particular 120 students had a mean CD collection size of 80 CDs. Select the correct description of the population in this study.
Complete Question
A few years ago, people tended to have relatively large CD collections. For students at a large university in the midwest, the mean number of CDs owned was 78 with a standard deviation of 90. To confirm these numbers, a random sample of 120 students from this university was collected and the size of their CD collections recorded. These particular 120 students had a mean CD collection size of 80 CDs. What is the numerical value of the sample mean?
Answer:
Sample Mean [tex]\=x=80[/tex]
Step-by-step explanation:
From the question we are told that:
Population Mean [tex]\mu=78[/tex]
Standard deviation [tex]\sigma=90[/tex]
Sample size [tex]n=120[/tex]
Sample Mean [tex]\=x=80[/tex]
Therefore
The numerical value of the sample mean is
Sample Mean [tex]\=x=80[/tex]
What is the measure of e?
Answer:
[tex] \theta = 4~radians [/tex]
Step-by-step explanation:
[tex] s = \theta r [/tex]
[tex] 20~cm = \theta \times 5~cm [/tex]
[tex] \theta = 4~radians [/tex]
Help me pls
I put the picture in the attach file below
(Sorry i'm in secondary school but i have a problem with my settings)
Step-by-step explanation:
0 is the ans my guy
dngjdjvkdkckgkdkgkskfkfkv
Which expression is equivalent to -28xy + 35y?
o 7y(-4xy + 5y)
O 7x{-4x+ 5y)
o 7xl-4y+54)
O 7y(-4x+5)
Answer:
[tex]-28xy+35y[/tex]
[tex]GCF ~is~ 7y[/tex]
[tex]=7y(-4+5)[/tex]
The equivalent expression: [tex]7y(-4x+5)[/tex]
-------------------------
hope it helps...
have a great day!!
Determine how much simple interest you would earn on the following investment:
$13,400 invested at a 6/2 % interest rate for 4 years.
Answer:
How do you mean 6/2%? Clarify it for assistance
Answer:
Simple interest = $ 3,484.00
Step-by-step explanation:
I= P×R×T ÷ 100
The rate is 6 1/2 and I will use the decimal form 6.5,to change that to a whole number we simply move the decimal point one place behind.
Since we moved the decimal point in the numerator we need to do the same for the denominator.Therefore 100 becomes 1000.
13400 × 65 × 4 = $ 3,484.00
1000
2 The product of two numbers is 5425. If one of them is 25. What is the other 2 number
Answer:
217
Step-by-step explanation:
5425/25 = 217