Answer:
[tex]x=\frac{13}{2}+\frac{1}{2}\sqrt{149}[/tex]
Step-by-step explanation:
x=
−b±√b2−4ac
2a
x=
−(−13)±√(−13)2−4(1)(5)
2(1)
x=
13±√149
2
x=
13
2
+
1
2
√149 or x=
13
2
+
−1
2
√149
Daniel believes that people perform better in the barbell curl, on average, if they are encouraged by a coach. He recruited 29 subjects to participate in an experiment and randomly assigned them into two groups. Daniel gave one group verbal encouragement during the exercise and was quiet during the exercise for the other group. He recorded the total number of barbell curls each subject was able to complete before setting the bar down.
Explain the purpose of random assignment in this experiment.
Answer:
Define two roughly identical sets.
Reduce the chance of bias.
Step-by-step explanation:
In this experiment, Daniel performs a random assignment in order to stablish two separate groups with roughly equivalent ability to do barbell curls. Two different treatments (verbal encouragement and silence) are then applied in order to verify for a cause and effect relationship. If the groups were not randomly assigned, then the experiment could be biased.
A bag contains 10 Yellow, 4 Green and 7 Blue marbles. Find the following probabilies.
P(blue)
Answer:
1/3
Step-by-step explanation:
The total number of marbles
10+4+7 = 21
P(blue) = blue marbles / total marbles
= 7 / 21
= 1/3
White and black shapes are used in a game Some of the shapes are circles All the other shapes are squares The ratio of white to black shapes is 5:11 The ration of white circles to white squares is 3:7 The ratio of black circles to black squares is 3:8 What fraction of all the shapes are circles
Answer:
9/32
hope this helps
Helen is 8 years older than Jane. Twenty years ago Helen was three times as old as Jane. How old is each now?
If Jane's current age is x, the equation will be [ equation ]
Helen is [ ]
years old. Jane is [ ]
years old.
H = 8 + x
H - 20 = 3(x - 20)
8 + x - 20 = 3(x - 20)
x - 12 = 3x - 60
48 = 2x
24 = x (Jane) -->
33 = H (Helen)
Ms Davis is doing an activity with her statistic students where she gives them a 20 question multiple top choice test and they know none of the answers. Students need to guess on every question and each question has 5 possible choices, 1 of the which is correct.
What is the mean and standard deviation of the number of questions that each student gets correct?
Answer:
The mean and standard deviation of the number of questions that each student gets correct are 4 and 1.789 respectively.
Step-by-step explanation:
Let the random variable X be defined as the number of correct answers marked by a student.
It is provided that each question has 5 possible choices, 1 of the which is correct.
Then the probability of marking thee correct option is:
[tex]P(X)=\frac{1}{5}=0.20[/tex]
There are a total of n = 20 questions to be answered.
As the students does not the answer to any question, they would be guessing for each question. This implies that for a random question, all the five options has the equal probability of being correct and each of the five options can be correct independently from the other.
All these information above indicates that the random variable X follows a Binomial distribution with parameters n = 20 and p = 0.20.
The mean and standard deviation of a Binomial distribution are:
[tex]\mu=np\\\\\sigma=\sqrt{np(1-p)}[/tex]
Compute the mean and standard deviation of the random variable X as follows:
[tex]\mu=np=20\times 0.20=4\\\\\sigma=\sqrt{np(1-p)}=\sqrt{20\times 0.20\times(1-0.20)}=1.789[/tex]
Thus, the mean and standard deviation of the number of questions that each student gets correct are 4 and 1.789 respectively.
According to the question,
The probability of making 3 correct options will be:
→ [tex]P(X) = \frac{1}{5}[/tex]
[tex]= 0.20[/tex]
Total number of questions,
n = 20As we know,
The mean will be:
→ [tex]\mu = np[/tex]
By substituting the values, we get
[tex]= 20\times 0.20[/tex]
[tex]= 4[/tex]
and,
The standard deviation will be:
→ [tex]\sigma = \sqrt{np(1-p)}[/tex]
[tex]= \sqrt{20\times 0.20\times (1-0.20)}[/tex]
[tex]= 1.789[/tex]
Thus the responses above are correct.
Learn more about standard deviation here:
https://brainly.com/question/20896613
To measure the height of the cloud cover at an airport, a worker shines a spotlight upward at an angle 75° from the horizontal. an observer at a distance d = 560 m away measures the angle of elevation to the spot of light to be 45°. find the height h of the cloud cover,
Answer:
The height of the cloud cover is 441.66 meters
Step-by-step explanation:
Distance = 560 m
The height of the cloud cover = h meters
According to the diagram, the worker stands at point R,
Let RT = x
tan 45⁰ = [tex]\frac{opposite}{adjacent}[/tex] = [tex]\frac{h}{x}[/tex]
therefore, 1 = [tex]\frac{h}{x}[/tex], h = x
Then tan 75⁰ = [tex]\frac{h}{560-x}[/tex], substituting x = h, we have
3.732 = [tex]\frac{h}{560-h}[/tex]
3.732(560 - h) = h
3.732 × 560 = 3.732h + h
2089.92 = 4.732h
h = 441.66 m
The height of the cloud cover is 228.62 meters
The given parameters are:
[tex]\mathbf{\alpha = 75^o}[/tex]
[tex]\mathbf{\theta = 45^o}[/tex]
[tex]\mathbf{d = 560m}[/tex]
See attachment for the image of the cloud cover.
From the attached image, we have the following sine ratios:
[tex]\mathbf{sin(75) = \frac hx}[/tex]
[tex]\mathbf{sin(45) = \frac h{560 - x}}[/tex]
Make h the subject in both equations
[tex]\mathbf{ h = xsin(75)}[/tex]
[tex]\mathbf{ h = (560 - x) sin(45)}[/tex]
So, we have:
[tex]\mathbf{ xsin(75) = (560 - x) sin(45)}[/tex]
Open brackets
[tex]\mathbf{ xsin(75) = 560sin(45) - x sin(45)}[/tex]
Collect like terms
[tex]\mathbf{ xsin(75) + x sin(45)= 560sin(45) }[/tex]
Evaluate sine 45 and 75
[tex]\mathbf{ 0.9659x + 0.7071x= 560 \times 0.7071}[/tex]
[tex]\mathbf{ 1.673x= 395.976}[/tex]
Divide both sides by 1.673
[tex]\mathbf{ x= 236.69}[/tex]
Recall that:
[tex]\mathbf{ h = xsin(75)}[/tex]
So, we have:
[tex]\mathbf{h = 236.69 \times 0.9659}[/tex]
[tex]\mathbf{h = 228.618871}[/tex]
Approximate
[tex]\mathbf{h = 228.62}[/tex]
Hence, the height of the cloud cover is 228.62 meters
Read more at:
https://brainly.com/question/16979479
Write parametric equations of the line 2x - y = 3.
a. X = 1, y = 2t - 2
c.
X = 1, y = 3t-2
b. X= 1, y = 2t-3
d.
1
1
X = 1,y= =
2
1.9 -
3
Please select the best answer from the choices provided
A
OB
С
OD
What parallelogram has a base of 2 units and a height of 4 units
Answer:
C
Step-by-step explanation:
The parallelogram in C has a base of 2 units and a height o 4 units.
55 POINTS IF YOU GET RIGHT THEN GOATED AND BRAINIEST!!
Answer:
17 i would say it is D
18 i belive it is B
19 it is c
20 A
For the inverse variation equation xy = k, what is the constant of variation, k, when x = 7 and y = 3?
Answer:
k=21
Step-by-step explanation:
x=7 X y=3 = 21
7 x 3 = 21
Answer:21
Step-by-step explanation:
xy=k
k=xy x=7 y=3
k=7 x 3
k=21
Rewrite the percentage in the sentence below as a decimal.
The 20 overseas investors own 7.2% of the business.
Answer:
0.072
Step-by-step explanation:
Answer:0.072
Step-by-step explanation:
7.2% = 7.2/100
7.2 ➗ 100=0.072
add 5 1/2 kg to 450g
1kg = 1000g
51/2 kg= 51/2×1000=51×500=25500g
25500g+450g= 25950g
Answer:
[tex]5950g[/tex]
Step-by-step explanation:
[tex]5 \frac{1}{2} kg \\ = 5kg \: 500g \\ = 5500g[/tex]
Now let's add.[tex] \: \: \: \: \: \: 5500g \\ + \: \: \: \: 450g \\ =5950 g[/tex]
So the correct answer is,[tex] = 5950g = 5kg \: 950g[/tex]
hope this helps
brainliest appreciated
good luck! have a nice day!
Ginger still has 40 percent of her book to read. If she has read 180 pages, how many pages does she still have to read?
Answer:
Ginger still has 40 percent of her book to read. If she has read 180 pages, the number of pages she still have to read:
N = 180 x (100 - 40)/40 = 270 pages
Hope this helps!
:)
Subtracting by adding up 65-39
Answer:
26Step-by-step explanation:
In order to subtract by adding up 65-39, we need to add -39 to the value of 65. This can be rewritten in this way;
65+(-39)
The equation above is similar to the one given because the product of a minus and a plus sign will still give us back a minus sign.
on solving;
65+(-39) = 26
Gibbs Baby Food Company wishes to compare the weight gain of infants using its brand versus its competitor’s. A sample of 40 babies using the Gibbs products revealed a mean weight gain of 7.6 pounds in the first three months after birth. For the Gibbs brand, the population standard deviation of the sample is 2.3 pounds. A sample of 55 babies using the competitor’s brand revealed a mean increase in weight of 8.1 pounds. The population standard deviation is 2.9 pounds. At the .05 significance level, can we con- clude that babies using the Gibbs brand gained less weight? Compute the p-value and interpret it.
Answer:
[tex]z=\frac{(7.6-8.1)-0}{\sqrt{\frac{2.3^2}{40}+\frac{2.9^2}{55}}}}=-0.936[/tex]
The p value can be founded with this formula:
[tex]p_v =P(z<-0.936)=0.175[/tex]
Since the p value is higher than the significance level provided of 0.05 we have enough evidence to FAIL to reject the null hypothesis and we can't conclude that the true mean for the Gibbs brand is significantly lower than the true mean for the competitor
Step-by-step explanation:
Information given
[tex]\bar X_{1}=7.6[/tex] represent the mean for Gibbs products
[tex]\bar X_{2}=8.1[/tex] represent the mean for the competitor
[tex]\sigma_{1}=2.3[/tex] represent the population standard deviation for Gibbs
[tex]\sigma_{2}=2.9[/tex] represent the sample standard deviation for the competitor
[tex]n_{1}=40[/tex] sample size for the group Gibbs
[tex]n_{2}=55[/tex] sample size for the group competitor
[tex]\alpha=0.05[/tex] Significance level provided
z would represent the statistic
Hypothesis to verify
We want to check if babies using the Gibbs brand gained less weight, the system of hypothesis would be:
Null hypothesis:[tex]\mu_{1}-\mu_{2}=0[/tex]
Alternative hypothesis:[tex]\mu_{1} - \mu_{2}< 0[/tex]
The statistic would be given by:
[tex]z=\frac{(\bar X_{1}-\bar X_{2})-\Delta}{\sqrt{\frac{\sigma^2_{1}}{n_{1}}+\frac{\sigma^2_{2}}{n_{2}}}}[/tex] (1)
Replacing the info given we got:
[tex]z=\frac{(7.6-8.1)-0}{\sqrt{\frac{2.3^2}{40}+\frac{2.9^2}{55}}}}=-0.936[/tex]
The p value can be founded with this formula:
[tex]p_v =P(z<-0.936)=0.175[/tex]
Since the p value is higher than the significance level provided of 0.05 we have enough evidence to FAIL to reject the null hypothesis and we can't conclude that the true mean for the Gibbs brand is significantly lower than the true mean for the competitor
What is the solution to the system of equations?
3 x + 10 y = negative 47. 5 x minus 7 y = 40.
(1, –5)
(1, 5)
(–1, –5)
(–1, 5)
Answer:
(1, –5)
Step-by-step explanation:
It is relatively easy to try the offered solutions to see what works.
(1, -5)
3(1) +10(-5) = -47 . . . true
5(1) -7(-5) = 40 . . . true
(1, -5) is the solution
_____
As a check, you can try some of the other choices:
(1, 5)
3(1) +10(5) ≠ -47
(-1, -5)
3(-1) +10(-5) ≠ -47
(-1, 5)
3(-1) +10(5) ≠ -47
None of the other choices works in the first equation, so they're not the solution.
Answer:
(1,-5)
Step-by-step explanation:
1)get desmos
2)put in numbers
3)where they intersect is the answer.
easy as pie... oh wait pie ain't easy...
easy as ramen
The corresponding sides of ΔABC and ΔDEF have equal lengths. The area of ΔABC is 4 square units, and the longest side of ΔDEF is 5 units long. What is the area of ΔDEF?
Answer:
4 square units
Step-by-step explanation:
If corresponding sides have equal lengths, the triangles are congruent by the SSS postulate. They must have equal areas: 4 square units.
ΔDEF has an area of 4 square units.
Answer:
if the corresponding sides are equal the 2 triangles are congruent ( by SSS) so their areas are the same.
So area of triangle DEF = 4 sq units
Step-by-step explanation:
Carpetland carpet installers incur an average cost of $300 for each carpet installed. Joan Chin, the firm’s vice president, proposes a new procedure for installations, which she hopes will be more efficient. Joan plans to run a trial and hopes that the results of a trial period will enable her to conclude with a level of significance of 0.05 that the new procedure reduces the average cost to install a carpet. If Joan's hypothesis test results in a Type II error, what would this mean?
Answer:
A Type II error happens when the null hypothesis failed to be rejected, although it is false and the alternative hypothesis is true.
In this context, would be that the test does not give enough evidence to support the claim that the new procedure reduces the average cost, although it really does reduces it.
The new procedure is effective, but the sample does not give enough evidence.
Step-by-step explanation:
Really need help on this. I keep gettin it wrong please help!!!
Answer:
1436.76 m³
Step-by-step explanation:
Volume of sphere= 4/3 π r ³
V= 4/3(3.14)(7)³
V=4/3(3.14)(343)
V= 4310.26 / 3
V= 1436.76 m³
simplify the expression (3k / 8)^2
Answer:
9k/64^2 (9k^2/64^2)
Step-by-step explanation:
Answer:
9k^2/64
Step-by-step explanation:
3*3=9
k*k=k^2
8*8=64
If f(x)=9x+2, What is the value of the function when x=4?
If f(x)=9x+2, for what value of x is the value of the function 29?
Answer:
1) 38
2) 3
Step-by-step explanation:
f(x)=36+2
f(x)=38
29=9x+2
27=9x
x=3
Question: What is the value of the function at x=−2?
Answer: y=2
Step-by-step explanation: I took the test.
*THIS IS THE CORRECT ANSWER. PLEASE DON'T ANSWER 3. IT IS WRONG!*
You need to be taller than 48" to ride the roller coaster. Which of the following inequalities shows the height Susan has to be to ride the roller coaster.
h < 48"
h > 48"
h ≤ 48"
h ≥ 48"
Answer:
> 48"
Step-by-step explanation:
> represents greater than 48"
Solve each equation.
13 = -2w
Answer:
w = -6.5
Step-by-step explanation:
We want to get rid of the coefficient of w so that we can solve for w. To do that, let's divide both sides of the equation by -2. When we do so, we get -13/2 = w. Hope this helps!
I really need some HELP.............
Answer:
119000
Step-by-step explanation:
The median is the middle value when placed from smallest to largest
95000, 112000, 126000, 13000
The middle is between 112000 and 126000 so take the average
(112000+126000)/2 =238000/2 =119000
c. two hundred thirty-one and five tenths - in decimal standard form
Answer:
231.5
five tenths = 0.5
Simplify the radical below.
Square root 84
A. 221
B. 242
C. 4.21
D. 4.42
Pls no explanation will give you 20 points in in a hurry
the answer is B
Step-by-step explanation:
and I would love 20 points
A ball is thrown straight up from a cliff. The function f(x)= -4.9t^ + 17t +19 describes the height of the ball, in meters, as a function of time, t, in seconds. What is the maximum height of the ball? At what time is the height reached? Round your answer to one decimal place.
Answer:
33.7 m at 1.7 seconds
Step-by-step explanation:
For quadratic ax^2+bx+c, the line of symmetry (x-coordinate of the vertex) is ...
-b/(2a)
For your quadratic, the vertex (highest point) is reached at time ...
t = -(17)/(2(-4.9)) = 17/9.8 ≈ 1.7 . . . . seconds
__
The height at that time is ...
f(17/9.8) = (-4.9(17/9.8) +17)(17/9.8) +19 = 289/19.6 +19 ≈ 33.7 . . . meters
_____
Comment on the function evaluation
We have used the "Horner form" of the function to make evaluation easier.
f(t) = (-4.9t +17)t +19
of 30 students , 1/3 play sports. Of those who play sports, 2/5 play soccer. How many students play soccer?
Answer:
10 ppl play sport. 2/5= 4/10 so 4 ppl play soccer
Step-by-step explanation:
How many boys are there in an introductory geology course if 360 students are enrolled and there are five boys to every seven girls?
Answer:150 branliest
Step-by-step explanation:
Answer:
150
Step-by-step explanation:
360/(5+7)=30
30*5=150
Employees at a manufacturing plant have seen production
rates change by approximately 105% annually. In contrast,
the graph shows the change in the average annual wages
of the employees
Which statement accurately compares the annual change
in production to the annual change in average salary?
50.000
50.000
0 The annual changes cannot be compared because the
initial production value is unknown.
The annual change in production will, at some point,
exceed the annual change in average salary
The annual change in production increases at a slower
rate, 5% per year, than the annual increase in the
average salary, $500 per year.
The annual change in production increases at a slower
rate, 105% per year, than the annual increase in average
salary, $500 per year
40
30.000
20.000
10.000
Answer:
both measures show strong growth in CEO
Step-by-step explanation:
350 firms in 2018 was $17.2 million- or $14.0 both show that they have a strong growth in the last 2 years.
Answer:
The answer is B "The annual change in production has exceeded the annual change in the average salary."
Step-by-step explanation:
Yes
