Answer: 10
Step-by-step explanation:
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
The circle graph shows how Spencer spent his money in the month of July.
A circle graph representing Spencers expenses. 27 percent is clothing, 11 percent is Gasoline, 44 percent is Food and 18 percent is Entertainment.
Part A
If Spencer spent a total of $704.00 in the month of July, which is the best estimate for the amount of money he spent on clothing?
$70.00
$140.00
$210.00
$280.00
00:00
Part B
Which is the best estimate for the amount of money he spent on entertainment?
$140.00
$35.00
$105.00
$160.00
Answer:
$190.08
Step-by-step explanation:
Take 27% of the total $704 spent in July:
0.27($704) = $190.08
He spent an estimated $190.08 on clothing in July.
Answer:
Step-by-step explanation:
I THINK 140
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
If you roll a die three times, what is the probability of rolling three ONES?
(Give your answer as a decimal, rounded to the nearest thousandth. That is, rounded to three decimal places.)
Answer:
0.004
Step-by-step explanation:
The probability of rolling any number is 1/6 so that times 3 is 1/216 that as a decimal i 0.004
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!
A sphere is inscribed in a cube. Explain the relationship between the surface areas of the two solid figures
Answer:
No one knows. Jk just go look at the other brainly links. the question has already been asked and answered so you can go see them there.
Step-by-step explanation:
:)
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"
Points X( -6, -4), Y( -2, -8), Z( 2,-4) are the vertices of a right triangle. What is the area of XYZ? Round to the nearest tenth.
Answer:
16
Step-by-step explanation:
distance between point x and z is 8 units
distance between point z and y is 4 units
8 * 4 = 32
formula for area of a triangle (l * w)/2
plugin: (8 * 4)/2 = 16
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
Priscilla’s grandmother’s fruit salad recipe calls for one part apple, one part orange, four parts strawberry, two parts cherry, and three parts grape. Priscilla uses the same measuring cup to measure all of the fruit, so one part is equal to one cup of diced fruit. In this exercise, you will compare the quantities in the recipe to understand ratios better.
Answer:
There are 11 parts of fruit: 4-strawberry, 3- grape, 2, cherry, 1- apple, 1-orange 4/11 from the entine quantity of fruits- strawberry
3/11-grapes
2/11- cherries
1/11- apples
1/11- oranges } ⇒ the quantity of oranges and apples are equal Hope it helps ;>
what is this phrase in numerical expression
triple the sum of seventeen and ten
pls help
Answer: so you would do 17 plus ten which is 27 so triple 3 so your answer is 27^3
Step-by-step explanation:
sum so your adding plus you need the exponent which is times 3
The management of Discount Furniture, a chain of discount furniture stores in the Northeast, designed an incentive plan for salespeople. To evaluate this innovative plan, 12 salespeople were selected at random, and their weekly incomes before and after the plan were recorded. Was there a significant increase in the typical salesperson’s weekly income due to the innovative incentive plan? Use the .05 significance level. Estimate the p-value, and interpret it
Answer:
Step-by-step explanation:
The question is incomplete. The complete question is
The management of Discount Furniture, a chain of discount furniture stores in the Northeast, designed an incentive plan for salespeople. To evaluate this innovative plan, 12 salespeople were selected at random, and their weekly incomes before and after the plan were recorded.
Salesperson Before After
Sid Mahone $320 $340
Carol Quick 290 285
Tom Jackson 421 475
Andy Jones 510 510
Jean Sloan 210 210
Jack Walker 402 500
Peg Mancuso 625 631
Anita Loma 560 560
John Cuso 360 365
Carl Utz 431 431
A. S. Kushner 506 525
Fern Lawton 505 619
Solution:
Corresponding income of salespersons before and after form matched pairs.
The data for the test are the differences between the income is salespersons.
μd = the income before minus their income after.
Bedore after diff
320 340 -20
290 285 5
421 475 - 54
510 510 0
210 210 0
402 500 - 98
625 631 -6
569 560 0
360 365 - 5
431 431 0
506 525 - 19
505 619 - 114
Sample mean, xd
= (- 20 + 5 - 54 + 0 + 0 - 98 - 6 + 0 - 5 + 0 + - 19 - 114)/12 = - 25.92
xd = - 25.92
Standard deviation = √(summation(x - mean)²/n
n = 12
Summation(x - mean)² = (- 20 + 25.92)^2 + (5 - 25.92)^2 + (- 54 + 25.92)^2+ (0 + 25.92)^2 + (0 + 25.92)^2 + ( - 98 + 25.92)^2 + ( - 6 + 25.92)^2 + (0 + 25.92)^2 + (- 5 + 25.92)^2 + (0 + 25.92)^2 + (- 19 + 25.92)^2 + (- 114 + 25.92)^2 = 17784.5168
Standard deviation = √(17784.5168/12
sd = 38.5
For the null hypothesis
H0: μd ≥ 0
For the alternative hypothesis
H1: μd < 0
1) The distribution is a students t. Therefore, degree of freedom, df = n - 1 = 12 - 1 = 11
2) The formula for determining the test statistic is
t = (xd - μd)/(sd/√n)
t = ( - 25.92- 0)/(38.5/√12)
t = - 2.33
3) We would determine the probability value by using the t test calculator.
p = 0.02
4) Assume alpha = 0.05
Since alpha, 0.05 > than the p value, 0.02, then we would reject the null hypothesis. We can conclude that at 5% significance level, there is a significant increase in the typical salesperson’s weekly income due to the innovative incentive plan
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:
Please help ASAP! I will mark Brainliest! Please answer CORRECTLY! No guessing!
Answer:
Option D: 5591.93
Step-by-step explanation:
The best way to understand this question is to apply the formula in an indirect manner;
P - Principle number, Starting Value
T - Time
I - Interest
Let us convert the interest into decimal form, such that 3.8% is shifted two decimal points to the right ⇒ 0.038. Now add 1 to this value to get ⇒ 1.038. By PEDMAS, you would first raise this value to the span of 3 years as such:
(1.038)^3 = 1.118386872.......
The final step would by to multiply the starting value (investment $) $ 5,000 by this continuing value of 1.118386872:
5,000(1.118386872) = 5591.93436 ⇒ Rounded to (About) 5591.93
Answer:D
Step-by-step explanation:
principal=p=$5000
Rate=r=3.8%
Time=n=3 years
amount=a
a=p(1+r/100)^n
a=5000(1+3.8/100)^3
a=5000(1+0.038)^3
a=5000(1.038)^3
a=5000 x 1.038 x 1.038 x 1.038
a=5591.93
a=$5591.93
Please help ASAP! I will mark Brainliest! Please READ the question THEN answer CORRECTLY! No guessing!
Answer:
C. [tex]\frac{\sqrt{5} }{8}[/tex]
Step-by-step explanation:
This expression can be rewritten as [tex]\frac{\sqrt{5} }{\sqrt{64} }[/tex].
Since the square root of 5 is prime and does not have any perfect square factors, it cannot be simplified. However, the square root of 64 is equal to 8, so our final simplified radical expression would be [tex]\frac{\sqrt{5} }{8}[/tex], which is option C.
HOPE THIS HELPED! :)
Answer:
C is the answer
Step-by-step explanation:
You have to rewrite as [tex]\sqrt{5}[/tex]/[tex]\sqrt{64}[/tex]. Then you have to simplify the denominator which is 8. That is how you get your answer.
Hope this helps.
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!*
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!
the midpoint of AB is point P at (-16,6) if point A is at (-10,8) what are the coordinates of point B?
Answer:
Denote B(x, y), we have:
-10 + x = 2 x (-16) => x = -22
8 + y = 2 x 6 => y = 4
=> B(-22, 4)
Hope this helps!
:)
Find the greatest common factor of the
following monomials:
34c3 2c5
Answer:2c^2
Step-by-step explanation:
34c^3 and 2c^5
34c^3=2 x 16 x c x c^2
2c^5=2 x c^2 x c^3
Greatest common factor =2 x c^2
Greatest common factor =2c^2
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
please answer these, it is urgent
Answer: 1 is D
2 is c
Step-by-step explanation:
Which fraction equals a repeating decimal?
30/50
13/25
5/30
13/10
Answer:
5/30
Step-by-step explanation:
5/30 = 1/6 =0.166666666...
The fraction equals a repeating decimal is 5/30.
What are decimals?A decimal numeral system is the standard system for denoting integer and non-integer numbers. The way of denoting numbers in the decimal system is often referred to as decimal notation.
Now the given fractions are,
30/50
13/25
5/30
13/10
Converting them into decimals we get,
30/50 = 0.6
13/25 = 0.52
5/30 = 0.1666..
13/10 = 1.3
Thus the repeating decimal is 0.1666..
So, the fraction with repeating decimal is 5/30 = 0.1666..
Thus, the fraction equals a repeating decimal is 5/30.
To learn more about fraction :
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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
Writing Percents as Fractions
a. Write 35% as a fraction in simplest form.
35% =
35
100
Write as a fraction with
a denominator of 100.
7
20
Simplity.
Answer:
Answers are below
Step-by-step explanation:
Percent means "out of 100" so 35% is 35/100. We can simplify this fraction by dividing the numerator and denominator by 5. 35/100 / 5 = 7/20.
7/20 multiply the numerator and denominator by 5.
7/20 x 5 = 35/100
If this answer is correct, please make me Brainliest!
Answer:
b and c
Step-by-step explanation:
A grocery store has an average sales of $8000 per day. The store introduced several advertising campaigns in order to increase sales. To determine whether or not the advertising campaigns have been effective in increasing sales, a sample of 64 days of sales was selected. It was found that the average was $8300 per day. From past information, it is known that the standard deviation of the population is $1200. The p-value is
Answer:
The p-value of the test is 0.023.
Step-by-step explanation:
In this case we need to determine whether the addition of several advertising campaigns increased the sales or not.
The hypothesis can be defined as follows:
H₀: The stores average sales is $8000 per day, i.e. μ = 8000.
Hₐ: The stores average sales is more than $8000 per day, i.e. μ > 8000.
The information provided is:
[tex]n=64\\\bar x=\$8300\\\sigma=\$1200[/tex]
As the population standard deviation is provided, we will use a z-test for single mean.
Compute the test statistic value as follows:
[tex]z=\frac{\bar x-\mu}{\sigma/\sqrt{n}}=\frac{8300-8000}{1200/\sqrt{64}}=2[/tex]
The test statistic value is 2.
Decision rule:
If the p-value of the test is less than the significance level then the null hypothesis will be rejected.
Compute the p-value for the two-tailed test as follows:
[tex]p-value=P(Z>2)\\=1-P(Z<2)\\=1-0.97725\\=0.02275\\\approx 0.023[/tex]
*Use a z-table for the probability.
The p-value of the test is 0.023.
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
The sum of the measures of the angles of a triangle is 180. The sum of the measures of the second and third angles is five times the measure of the first angle. The third angle is 14 more than the second. Let x, y, and z represent the measures of the first, second, and third angles, respectively. Find the measures of the three angles.
Answer:
[tex]x=30\\y=68\\z=82[/tex]
Step-by-step explanation:
x = measure of the first angle
y = measure of the second angle
z = measure of the third angle
The sum of the measures of the second and third (y+z) is five times the measure of the first angle (=5x)
[tex]y+z=5x[/tex]
The third angle is 14 more than the second
[tex]z=y+14[/tex]
And remember that the sum of these three angles must be equal to 180.
[tex]x+y+z=180[/tex]
Let's take these equations
[tex]y+z=5x\\z=y+14\\x+y+z=180[/tex]
If you take a look at the first equation, we have y+z = 5x and we have y+z in the third equation as well, we can replace that....
[tex]x+y+z=180\\x+(y+z)=180\\x+(5x)=180[/tex]
Distribute the + sign
[tex]x+5x=180[/tex]
Combine like terms;
[tex]6x=180[/tex]
Divide by 6.
[tex]x=\frac{180}{6}\\ x=30[/tex]
We have now defined that the measure of the first angle is 30º.
Let's take another equation... for example [tex]z=y+14[/tex]
I'm going to take this one because if I replace x and z in the third equation, all I'll have left will be y.
[tex]x+y+z=180\\30+y+(y+14)=180[/tex]
Distribute the + sign and Combine like terms;
[tex]30+y+y+14=180\\44+2y=180\\[/tex]
Subtract 44 to isolate 2y.
[tex]2y=180-44\\2y=136[/tex]
Now divide by 2.
[tex]y=\frac{136}{2}\\ y=68[/tex]
We already have the value of x and y. Once again, replacing this in the third equation will leave us with z to solve for.
[tex]x+y+z=180\\30+68+z=180\\98+z=180\\z=180-98\\z=82[/tex]
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
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
Find the surface area of the pyramid to the nearest whole number.
Answer:
i think its 248m^2
Step-by-step explanation: