Vitamin D is important for the metabolism of calcium and exposure to sunshine is an important source of vitamin D. A researcher wanted to determine whether osteoperosis was associated with a lack of exposure to sunshine. He selected a sample of 250 women with osteoperosis and an equal number of women without osteoperosis. The two groups were matched - in other words they were similar in terms of age, diet, occupation, and exercise levels. Histories on exposure to sunshine over the previous twenty years were obtained for all women. The total number of hours that each woman had been exposed to sunshine in the previous twenty years was estimated. The amount of exposure to sunshine was compared for the two groups. Group of answer choices
Answer:
The type of observational study describer here is retrospective study.
Step-by-step explanation:
The complete question is:
Vitamin D is important for the metabolism of calcium and exposure to sunshine is an important source of vitamin D. A researcher wanted to determine whether osteoperosis was associated with a lack of exposure to sunshine. He selected a sample of 250 women with osteoperosis and an equal number of women without osteoperosis. The two groups were matched - in other words they were similar in terms of age, diet, occupation, and exercise levels. Histories on exposure to sunshine over the previous twenty years were obtained for all women. The total number of hours that each woman had been exposed to sunshine in the previous twenty years was estimated. The amount of exposure to sunshine was compared for the two groups. Determine what type of observational study is described. Explain.
Solution:
In retrospective study design, the concerned outcome has previously taken place in each participant by the phase he or she is signed up for the study, and the information are gathered either from past data or by requesting the participants to recall exposures.
It is also known as a historic cohort study.
A retrospective study is completed as posterior experiment, using data on events that have already taken place in the history. In most cases some or most of the data has already been collected and stowed in the archive.
In the provided scenario, the researcher collect the past data for the exposure to sunshine over the previous twenty years for 250 women. And estimated the total number of hours that each woman had been exposed to sunshine in the previous twenty years.
Then the researcher compares the amount of exposure to sunshine for the two groups.
Thus, the type of observational study describer here is retrospective study.
Mary is running a marathon which is a total of 26 miles. She is running at a pace of 7.5 miles per hour and
has already run 8 miles. If she stays at the same pace, how much time in hours does she have left?
Answer:
2.4 hours
Step-by-step explanation:
If Mary is running 26 miles at a pace of 7.5 miles per hour, it will take her 3.47 hours to run the full course.
26/7.5 = 3.466666...
If she has run 8 miles, 1.07 hours have passed.
8/7.5 = 1.06666666...
Subtract the total time from the time that has already passed to find the time left.
3.47 - 1.07 = 2.4
Mary has 2.4 hours left.
The local food pantry has 1, 600 cans of fruit. They give away 155 cans of fruit each week. Assuming no new donations are made,
how many cans of fruit will remain after 6 weeks?
The solution is
What is the answer for this problem?
Answer:
670 Cans of fruit will be left
Step-by-step explanation:
First you multiply 155 by the 6 weeks.
That equals 930 and then you subtract 930 from 1,600 and that gives you 670.
There are 670 cans of fruit that will remain after 6 weeks the answer is 670 cans.
What is a sequence?It is defined as the systematic way of representing the data that follows a certain rule of arithmetic.
We have:
The local food pantry has 1, 600 cans of fruit. They give away 155 cans of fruit each week.
First term a = 1600
Common difference d = -155
After 6 weeks means on week 7.
n = 7
a(7) = 1600 + (7-1)(-155)
a(7) = 1600 - 930
a(7) = 670
Thus, there are 670 cans of fruit that will remain after 6 weeks the answer is 670 cans.
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2ft/sec is how many mph?
Answer:
1.36364
Step-by-step explanation:
I calculated the solution on a calculator
So the answer to 1 d.p is 1.4
The average age of all students at a certain college is 22 years and the standard deviation is 2 years. What is the probability that the average age of a randomly selected sample of 100 students will be less than 21.8 years
Answer:
The probability that the average age of a randomly selected sample of 100 students will be less than 21.8 years is 0.159
Step-by-step explanation:
According to the given data we have the following:
mean = μ= 22
standard deviation = σ = 2
n = 100
μx = 22
σx=σ/√n=2/√100=0.2
Therefore, P( x < 21.8)=P(x-μx)/σx<(21.8-22)/0.2
=P(z<-1)
= 0.159
The probability that the average age of a randomly selected sample of 100 students will be less than 21.8 years is 0.159
I need help for a grade
Answer:
180
Step-by-step explanation:
2(24)-3=45
24-8=√16=4
45*4=180
Solve the equation x^3 + 2x^2 - 11x -12 = 0
Answer: there are 4 solutions
x = -2
x = -1/2 = -0.500
x =(3-√5)/2= 0.382
x =(3+√5)/2= 2.618
Step-by-step explanation:
HELP HELP HELP PLEASE!!!!!
A party rental company has chairs and tables for rent. The total cost to rent 2 chairs and 3 tables is $31. The total cost to rent 6 chairs and 5 tables is $59
What is the cost to rent each chair and each table?
Answer:
The rental of each chair is $2.75
The rental of each table is $8.5
Step-by-step explanation:
Let's name the unknowns "c" for the cost of each chair rental, and "t" for the cost of each table rental.
Now we can create the equations that represent the statements:
a) "The total cost to rent 2 chairs and 3 tables is $31."
2 c + 3 t = 31
b) "The total cost to rent 6 chairs and 5 tables is $59."
6 c + 5 t = 59
now we have a system of two equations and two unknowns that we proceed to solve via the elimination method by multiplying the first equation we got by "-3" so by adding it term by term to the second equation, we eliminate the variable "c" and solve for "t":
(-3) 2 c + (-3) 3 t = (-3) 31
-6 c - 9 t = -93
6 c + 5 t = 59
both these equations added give:
0 - 4 t = -34
t = 34/4 = 8.5
So each table rental is $8.5
now we find the rental price of a chair by using any of the equations:
2 c + 3 t = 31
2 c + 3 (8.5) = 31
2 c + 25.5 = 31
2 c = 5.5
c = 5.5/2
c = $2.75
A marketing consulting group wants to see whether placing a seasonal cookie product on an end cap (the shelf at the end of an aisle at a store) will make a difference in sales. The average sales of the seasonal cookie for this region was 650 units. A sample of 36 stores that placed the cookie on an end cap showed a sample mean of 671 units sold with a standard deviation of 81. The resulting p-value is 0.1288; thus, the null hypothesis is not rejected. The marketing consulting group concludes that placing the cookies on an end cap does not affect sales. What type of error is possible in this situation
Answer:
Type II error.
Step-by-step explanation:
We have a hypothesis test for the claim that placing a seasonal cookie product on an end cap (the shelf at the end of an aisle at a store) will make a difference in sales.
The null hypothesis will state that there is no difference, while the alternative hypothesis will state that there is significant positive difference.
The result is a P-value of 0.1288 and the null hypothesis failing to be rejected.
As the null hypothesis failed to be rejected, if an error has been made in the conclusion, is that we erroneusly accept a false null hypothesis.
This is a Type II error, where the null hypothesis is accepted although the alternative hypothesis is true.
Consider the graph of the line of best fit, y = 0.5x + 1, and the given data points. A graph shows the horizontal axis numbered negative 4 to positive 4 and the vertical axis numbered negative 4 to positive 4. Points show an upward trend. Which is the residual value when x = 2? –2 –1 1 2
Answer
its -1
Step-by-step explanation:
ED 2020 boiiiii
The residual value of the line of the best fit when x = 2 is -1
How to determine the residual value?The equation of the line is given as:
y = 0.5x + 1
When x = 2, we have:
y = 0.5 * 2 + 1
Evaluate
y = 2
The residual is the difference between the actual value and the predicted value.
From the complete graph, the actual value is 1.
So, we have:
Residual = 1 - 2
Evaluate
Residual = -1
Hence, the residual value when x = 2 is -1
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What is the ratio 28 : 4 in it's simplest form?
Answer:
7:1
Step-by-step explanation:
28:4=
7(4):1(4)=
7:1
Hope this helps!
Answer:
[tex]7:1[/tex]
Step-by-step explanation:
[tex]28:4[/tex]
Common highest factor is 4.
Simplify the ratio.
[tex]28 \div 4 : 4 \div 4[/tex]
[tex]7:1[/tex]
Divide: (y2−4y+6)÷(y+1).
Answer:
Step-by-step explanation:
hello
[tex]y^2-4y+6= (y+1)^2-2y-1-4y+6=(y+1)^2-6y+5=(y+1)^2-6(y+1)+11[/tex]
so
[tex]\dfrac{y^2-4y+6}{y+1}=y+1-6+\dfrac{11}{y+1}=y-5+\dfrac{11}{y+1}[/tex]
hope this helps
what are the steps (2+2i)(5+3i)??? please help me
Find the slope of the line that goes through the given points.
(6,1) and (9,-1)
Answer:
m = -2/3
Step-by-step explanation:
Slope Formula: [tex]m = \frac{y2-y1}{x2-x1}[/tex]
So,
[tex]m = \frac{-1-1}{9-6}[/tex]
m = -2/3
Find the range of the function f(x) = -x 2 + 4x if the domain is {-2, 0, 1}.
Answer:
y≤4
Step-by-step explanation:
y≤4
try to graph it on a parabola and u will find the answer above :D hope this helped
The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. According to the Standard Deviation Rule, almost all (99.7%) of the students spent on textbooks in a semester:______.A. Between 230 and 240 dollars.B. Between 220 and 250 dollars.C. Between 175 and 295 dollars.D. Less than 220 dollars or more than 250 dollars.E. Less than 230 dollars or more than 240 dollars.
Answer:
C. Between 175 and 295 dollars.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 235
Standard deviation = 20
According to the Standard Deviation Rule, almost all (99.7%) of the students spent on textbooks in a semester:
Within 3 standard deviations of the mean.
235 - 3*20 = 175
235 + 3*20 = 295
So the correct answer is C.
Two similar circles are shown. The circumference of the larger circle, with radius OB, is 3 times the circumference of the smaller circle, with radius OA. Two circles are shown. The smaller circle has radius O A and the larger circle has radius O B. Radius OB measures x units. Which expression represents the circumference of the smaller circle with radius OA? (StartFraction pi Over 3 EndFraction)x units (StartFraction 2 pi Over 3 EndFraction)x units 2πx units 6πx units
Answer:
its 2pi/3
Step-by-step explanation:
because the full radian measure of a circle is 2pi radians, the smaller circle is a third of the size of the larger one. Multiply straight across for (2pi/1)(1/3)
The circumference of the smaller circle can be given by [tex]\dfrac{2\times \pi}{m}(x)\ units[/tex].
Given to us,Two similar circles are shown.The circumference of the larger circle, with radius OB, is 3 times the circumference of the smaller circle, with radius OA. The smaller circle has radius O A and the larger circle has radius O B. Radius OB measures x units. Circumference of the larger circle[tex]\rm{Circumference\ of\ the\ circle = 2\times \pi \times (radius)[/tex]
[tex]\rm{Circumference\ of\ the\ circle = 2\times \pi \times (OB)[/tex]
[tex]\rm{Circumference\ of\ the\ circle = 2\times \pi \times (x)[/tex]
Circumference of the smaller circle,Circumference of the Larger circle = 3 x Circumference of the smaller circle
[tex]2\times \pi \times x = 3\times Circumference\ of\ the\ smaller\ circle\\\\3\times Circumference\ of\ the\ smaller\ circle = 2\times \pi \times x \\\\Circumference\ of\ the\ smaller\ circle = \dfrac{2\times \pi \times x }{3}\\\\Circumference\ of\ the\ smaller\ circle = \dfrac{2\times \pi}{3}( x )\ units[/tex]
Hence, the circumference of the smaller circle can be given by [tex]\dfrac{2\times \pi}{m}(x)\ units[/tex].
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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
0 .10 .04 .02
x 1 .08 .20 .06
2 .06 .14 .30
a. What is P(X = 1 and = 1)?
b. Compute P(X land Y 1).
c. Give a word description of the event {X t- 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 5 1)?
e. Are X and Y independent rv's? Explain.
Answer:
Step-by-step explanation:
Y
p(x,y) 0 1 2
0 0.10 0.04 0.02
x 1 0.08 0.2 0.06
2 0.0 0.14 0.30
a) What is P(X = 1 and = 1)
From the table above we have
P(1,1) = 0.2
b) Compute P(X ≤ 1 and Y ≤ 1).
[tex]=p(0,0)+p(0,1)+p(1,0)+p(1,1)\\\\=0.1+0.04+0.08+0.2\\\\=0.42[/tex]
C)
Let A ={X ≠ 0 and Y ≠ 0}
p{X ≠ 0 , Y ≠ 0}
= p(1,1) + p(1,2) + p(2,1) + p(2,2)
= 0.20 + 0.06 + 0.14 + 0.30
=0.7
d) The possible X values are in the figure 0,1,2
[tex]p_x(0)=p(0,0)+p(0,1)+p(0,2)\\\\=0.1+0.04+0.02\\\\=0.16\\\\p_x(1)=p(1,0)+p(1,1)+p(1,2)\\\\=0.08+0.2+0.06\\\\=0.34\\\\p_x(2)=p(2,0)+p(2,1)+p(2,2)\\\\=0.06+0.14+0.3\\\\=0.5[/tex]
The possible Y values are in the figure 0,1,2
[tex]p_y(0)=p(0,0)+p(1,0)+p(2,0)\\\\=0.1+0.08+0.06\\\\=0.24\\\\p_y(1)=p(0,1)+p(1,1)+p(2,1)\\\\=0.04+0.2+0.14\\\\=0.38\\\\p_y(2)=p(0,2)+p(1,2)+p(2,2)\\\\=0.02+0.06+0.3\\\\=0.38[/tex]
So the probability of x ≤ 1 is
[tex]p(x\leq 1)=p_x(0)+p_x(1)\\\\=0.34+0.16\\\\=0.50[/tex]
e) From the table
[tex]p_x(x=1,y=1)=p(1,1)\\\\=0.2\\\\p_x(1)=0.34\\\\p_y(1)=0.38[/tex]
we multiply both together
0.34 x 0.38
=0.1292
Therefore p(1,1) is not equal px(1), py(1)
Hence x and y are not independent it is not equal
The measure of angle O is 600°. The polnt (x, y) corresponding to on the unit circle is?
Answer:
[tex](\frac{-1}{2} , \frac{-\sqrt{3} }{2} )[/tex]
Step-by-step explanation:
Memorize your unit circle.
Step 1: Subtract 360 from 600 degrees to find rotation
600° - 360° = 240°
Step 2: Either find coordinates from unit circle or convert to radians
240° = 4π/3
Step 3: Find coordinates
Find the point P on the line yequals=33x that is closest to the point (60 comma 0 )(60,0). What is the least distance between P and (60 comma 0 )(60,0)?
Answer:
[tex]18\sqrt{10}$ units[/tex]
Step-by-step explanation:
We are given the equation of the line y=3x and a point, say Q(60,0) outside of that line.
We want to find the point on the line y=3x which is closest to Q.
Let P(x,y) be the desired point. Since it is on the line y=3x, it must satisfy the line.
If x=a, y=3a, so the point P has the coordinates (a,3a).
Distance between point Q and P
[tex]=\sqrt{(60-a)^2+(0-3a)^2}\\D =\sqrt{10a^2-120a+3600}[/tex]
To minimize D, we find its derivative
[tex]\dfrac{dD}{da}=\dfrac{10a-60}{\sqrt{10a^2-120a+3600} }\\$Setting \dfrac{dD}{da}=0\\10a-60=0\\10a=60\\a=6[/tex]
Therefore, the y-coordinate for P is 3*6=18.
The point P=(6,18).
Next, we calculate the distance between P(6,18) and (60,0).
[tex]D =\sqrt{10(6)^2-120(6)+3600}\\=\sqrt{3240}\\=18\sqrt{10}$ units[/tex]
How do you determine the vertex from the vertex from of a quadratic equation
Answer:
it it the highest or lowest point of a parabola
insert a digit to make numbers that are divisible by 24 if it is possible 38_36
Answer:
ge
Step-by-step explanation:
ge
Approximately 8% of all people have blue eyes. Out of a random sample of 20 people, what is the probability that 2 of them have blue eyes? Round answer to 4 decimal places. Answer:
Answer:
27.11% probability that 2 of them have blue eyes
Step-by-step explanation:
For each person, there are only two possible otucomes. Either they have blue eyes, or they do not. The probability of a person having blue eyes is independent of any other person. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
8% of all people have blue eyes.
This means that [tex]p = 0.08[/tex]
Random sample of 20 people:
This means that [tex]n = 20[/tex]
What is the probability that 2 of them have blue eyes?
This is P(X = 2).
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 2) = C_{20,2}.(0.08)^{2}.(0.92)^{18} = 0.2711[/tex]
27.11% probability that 2 of them have blue eyes
The probability that 2 of them have blue eyes is 27.11%.
Given that,
Approximately 8% of all people have blue eyes.
Out of a random sample of 20 people,
We have to determine,
What is the probability that 2 of them have blue eyes?
According to the question,
People having blue eyes p = 8% = 0.08
Sample of people n = 20
For each person, there are only two possible outcomes. Either they have blue eyes, or they do not.
The probability of a person having blue eyes is independent of any other person.
The probability that 2 of them have blue eyes is determined by using a binomial probability distribution.
[tex]\rm P (X = x) =n_C_x\times p^x \times (1-p)^{n-x}}[/tex]
Therefore,
The probability that 2 of them have blue eyes is,
[tex]\rm P (X = x) =n_C_x\times p^x \times (1-p)^{n-x}}\\\\ \rm P (X = x) = \dfrac{n!}{(n-x)! \times x!} \times p^x \times (1-p)^{n-x}}\\\\[/tex]
Substitute all the values in the formula,
[tex]\rm P (X = 2) = \dfrac{20!}{(20-2)! \times 2!} \times (0.08)^2 \times (1-0.08)^{20-2}}\\\\ P (X = 2) = \dfrac{20!}{(18)! \times 2!} \times (0.0064) \times (0.92)^{18}}\\\\ P (X = 2) = \dfrac{19\times 20}{ 2} \times (0.0064) \times (0.222)\\\\ P(X = 2) = {19\times 10}\times (0.00142)\\\\P(X = 2) = 0.2711\\\\P(X = 2) = 27.11 \ Percent[/tex]
Hence, The required probability that 2 of them have blue eyes is 27.11%.
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In 2003, a school population was 903. By 2007 the population had grown to 1311. How much did the population grow between the year 2003 and 2007? How long did it take the population to grow feom 903 students to 1311 students? What is the average population growth per year?
Answer:
The average population growth per year is 102.
Step-by-step explanation:
From the given data, we can find the slope which will give us the average rate of change. Our points are:
[tex](2003, 903)\quad and \quad (2007, 1311)[/tex]
[tex]\mathrm{Slope}=\frac{y_2-y_1}{x_2-x_1}=\frac{1311-903}{2007-2003}\\\\m=102[/tex]
Best Regards!
The box plots show Devonte’s scores in Spanish and in French. Devonte inferred that his French scores have less variability than his Spanish scores. Which explains whether Devonte’s inference is correct?
Devonte is correct because the range is greater for French.
Devonte is correct because the interquartile range is less for French. Devonte is not correct because his highest grade is in Spanish.
Devonte is not correct because the interquartile range is less for Spanish.
Answer:
Devonte is correct because the interquartile range is less for French
Step-by-step explanation:
The first box plot at the top shows scores in Spanish, while the second box plot below it shows French scores.
Variability can be ascertain by finding out the interquartile range of a data set.
The higher the value of the IQR, the more the variability, while the lower the IQR, the less the variability.
IQR = Q3 - Q1
IQR for Spanish score = 85 - 60 = 25
IQR for French score = 80 - 65 = 20
From the above, we can say that Spanish scores has more variability when compared to French scores.
Therefore, Devonte is correct because the interquartile range is less for French, which shows that the variability in French scores is lesser than that of Devonte's Spanish scores.
Answer:
Devonte is correct because the interquartile range is less for French.
Step-by-step explanation:
The scoring range indicates the deviance from the standard values. It can only be inferred that the interquartile range is very narrow. In other words, there is less variability in the scores. Thus, a smaller quartile range means that there is less variability in the quantity being measured. The interqurtile range is the difference in the values of the the 75th percentile and the 25th percentile of a cumulative frequency distribution curve.
Leah has 28 more marbles than Dan. 1/3 of Leah’s marbles are equal in number to 4/5 of Dan’s marbles. Find the number of marbles Leah has.
Answer:
48
Step-by-step explanation:
L = D + 28
⅓L = ⅘D
Solve the system of equations using elimination or substitution. Using substitution:
⅓L = ⅘(L − 28)
Multiply both sides by 15:
5L = 12(L − 28)
Distribute:
5L = 12L − 336
Combine like terms:
336 = 7L
Divide:
L = 48
A student walk 60m on a bearing
of 028 degree and then 180m
due east. How is she from her
starting point, correct to the
nearest whole number?
Answer:
d = 234.6 m
Step-by-step explanation:
You can consider a system of coordinates with its origin at the beginning of the walk of the student.
When she start to walk, she is at (0,0)m. After her first walk, her coordinates are calculated by using the information about the incline and the distance that she traveled:
[tex]x_1=60cos28\°=52.97m\\\\y_1=60sin28\°=28.16m[/tex]
she is at the coordinates (52.97 , 28.16)m.
Next, when she walks 180m to the east, her coordinates are:
(52.97+180 , 28.16)m = (232.97 , 28.16)m
To calculate the distance from the final point of the student to the starting point you use the Pythagoras generalization for the distance between two points:
[tex]d=\sqrt{(x-x_o)^2+(y-y_o)^2}\\\\x=232.97\\\\x_o=0\\\\y=28.16\\\\y_o=0\\\\d=\sqrt{(232.97-0)^2+(28.16-0)^2}m=234.6m[/tex]
The displacement of the student on her complete trajectory was of 234.6m
Malik collects rare stamps and has a total of 212 stamps. He has 34 more domestic stamps than foreign stamps. Let x represent the number of domestic stamps and let y represent the number of foreign stamps. This system of equations models the given information for both stamp types. x – y = 34 x + y = 212 Solve the system of equations. How many foreign stamps does Malik have? foreign stamps How many domestic stamps does Malik have? domestic stamps
Answer:
foreign: 89domestic: 123Step-by-step explanation:
Add the two equations together:
(x -y) +(x +y) = (34) +(212)
2x = 246
x = 123
y = x-34 = 89
Malik has 89 foreign stamps and 123 domestic stamps.
Answer:
89 and 123
Step-by-step explanation:
What is the value of AC?
Answer:
0.637
Step-by-step explanation:
The average value of a whole sinusoidal waveform over one complete cycle is zero as the two halves cancel each other out
In a lottery daily game, a player picks three numbers from 0 to 9 (without repetition). How many different choices does the player have if order does not matter
Answer:
Not sure 3/10?
Step-by-step explanation:
numbers are 0-9...that's 10 choices.
he chooses 3 numbers
I would think 3/10?