In each case below, we describe a study to determine whether exercise helps increase certain mood enhancing chemicals in the brain. Indicate whether each describes an experiment or an observational study.
a). Using a random sample of 100 people, we randomly assign half of them to participate in a regular exercise program for a six-week period while the other half makes no changes. At the end of the time period, we measure the brain chemicals.
b). We contact a random sample of 100 people and record how much each person exercises and also measure the chemicals in the brain for each person.
Answer:
A)Experimental Study
B)Observational Study
Step-by-step explanation:
Observational Study : A study where researchers simply collect data based on what is seen and heard and infer based on the data collected.
Experimental Study: A study which involve the random assignment of -participants into different groups in order to determine the causal effect of a certain condition on a certain outcome .
A) In this case we are randomly classifying the subjects into two groups, where one group participate in a regular exercise program for a six week period, while the other half makes no changes. In this Part we are not observing the data . we are doing experiment over here and comparing those two different groups.
So, By definition It is an experimental study
B) In this case we are recording the data of each person and decision will be based on data
So, By definition It is an observational study
help plz explain how to use discributive property
1.Identify the fractions. Using the distributive property, you’ll eventually turn them into integers.
2.For all fractions, find the lowest common multiple (LCM) -- the smallest number that both denominators can fit neatly into. This will allow you to add fractions.
3.Multiply every term in the equation by the LCM.
4.Isolate variables adding or subtracting like terms on both sides of the equals sign.
5.Combine like terms.
6.Solve the equation and simplify, if needed.
Choose the SIMPLIFIED fraction that accurately represents the repeating decimal. (Each of these)
1. 0.333
2.0.454545
3.0.353535
4.242424
5.0.393939
Answer:
1) 1/3
2) 45/99
3) 35/99
4) 24/99
5) 39/99
Explanation:
1) 0.333 = 0.333/1 = 0.999/3 ≈ 1/3
2) 0.454545 ; 100x ≈ 45.45 ; x ≈ 0.45 ; 45.45-.45 = 45 ; 100x-x = 99 ; x = 45/99
3) 0.354535 ; 100x ≈ 35.35 ; x ≈ 0.35 ; 35.35-.35= 35; 100x-x = 99x ; x = 35/99
4) 0.242424 ; 100x ≈ 24.24 ; x ≈ 0.24 ; 24.24-.24 = 24 ; 100x-x = 99x ; x = 24/99
5) 0.393939 ; 100x ≈ 39.39 ; x ≈ 0.39 ; 24.24-.24 = 24 ; 100x-x = 99x ; x = 39/99
please help ??? Thanks
Answer:
Each y- value is determined by adding 4
Step-by-step explanation:
At a fabric store, fabrics are sold by the yard. A dressmaker spent $36.35 on 4.25 yards of silk and cotton fabrics for a dress. Silk is $16.90 per yard and cotton is $4 per yard.
Find the solution of the system of equations. Explain or show your reasoning
{x+y=4.25} ; {16.90x+4y=36.35}
Answer:
The number of yards of silk = x = 1.5 yards
The number of yards of cotton = y = 2.75yards
Step-by-step explanation:
At a fabric store, fabrics are sold by the yard. A dressmaker spent $36.35 on 4.25 yards of silk and cotton fabrics for a dress. Silk is $16.90 per yard and cotton is $4 per yard.
Find the solution of the system of equations. Explain or show your reasoning
{x+y=4.25} ; {16.90x+4y=36.35}
Let the number of yards of silk = x
The number of yards of cotton = y
We are given the system of equations:
{x+y=4.25} ......Equation 1
x = 4.25 - y
{16.90x+4y=36.35}....... Equation 2
4.25 - y for x in Equation 2
16.90(4.25 - y) + 4y = 36.35
71.825 - 16.90y + 4y = 36.35
71.825 - 36.35 = 16.90 - 4y
35.475 = 12.90y
y = 35.475/12.90
y = 2.75 yards.
The number of yards of cotton = y
{x+y=4.25} ......Equation 1
x = 4.25 - y
x = 4.25 - 2.75
x = 1.5 yards
The number of yards of silk = x = 1.5 yards
The yards of silk bought is 1.49 yards and the yard of cotton bought is 2.76 yards.
The two equations are known as simultaneous equation. They would be solved using elimination method.
x + y = 4.25 equation 1
16.90x + 4y = 36.25 equation 2
where:
x = yards of silk bought
y = yards of cotton bought
In order to determine the value of x, multiply equation 1 by 4.
4x + 4y = 17 equation 3
Subtract equation 3 from 2
19.25 = 12.90x
Divide both sides of the equation by 12.90
x = 1.49 yards
In order to determine the value of y, substitute for x in equation 1
1.49 + y = 4.25
y = 4.25 - 1.49
y = 2.76 yards
To learn more about simultaneous equations, please check: brainly.com/question/23589883?referrer=searchResults
angle 4 and angle 5 are ??? angles will mark brainiest
Answer:
Alternate interior
Step-by-step explanation:
They are inside making them interior angles and they are on opposite sides making them alternate angles as well.
Hope this helps!
Answer:
alternate interiorStep-by-step explanation:
alternate interior angles are congruent if and only lines are parallel.
∠4 ≅ ∠5
Express each ratio as a fraction in the simplest form. 12 pennies to 24 pennies
Answer: 1:2
Step-by-step explanation:
24 ÷ 12 = 2
12 ÷ 12 = 1
Answer to the question is 1:2
x + 4x + 4 - 8x
please help
Answer:
The answer is -13x+4
Gina read 120 pages in 4 days. Which reading rate is equivalent?
Answer:
Gina reads 30 pages per day.
Step-by-step explanation:
120 / 4 = 30
I hate to ask, but please give me Brainliest. I need it to level up <3.
Answer:
Gina reads 30 pages per day.
Step-by-step explanation:
CAN SOMEONE PLEASE DOUBLE CHECK IF THIS IS RIGHT!!! Please
Answer:
yes yesss yessssssssssssssssssssssssssssssssssss
MY TEACHER TEXTED ME THIS IDK WHAT TO EVEN DO:( help i luv u
Answer:
yea
same
Step-by-step explanation:
Answer:
well i hope you can figure it out
Step-by-step explanation:
4/5 of the cake was left, but after Brian ate some only 1/4 of the cake was left. Which fraction of the cake did Brian eat?
Answer:
3/4
Step-by-step explanation:
there was 4/5 you just had to minis 3and 4
Find the slope of the line through the pair of points: (6,12) and (-6, -2)
Answer: The answer would be 1
Step-by-step explanation:
Rise over run or fall over run so the fall is 10 and run is 10 and 10/10 is 1.
5x - 12=18
Solve for x
Answer:
x = 6
Step-by-step explanation:
Add 12 to each side, so it now looks like this: 5x = 30Divide each side by 5 to cancel out the 5 next to x. It should now look like this: x = 6I hope this helps!
Automated electron backscattered diffraction is now being used in the study of fracture phenomena. The following information is on misorientation angle (degrees).
Class: 0−<5 5−<10 10−<15 15−<20 20−<30 30−<40 40−<60 60−<90
Rel freq: 0.179 0.168 0.174 0.135 0.193 0.071 0.051 0.029
Is it true that more than 50% of the sampled angles are smaller than 15°, as asserted by researchers?
A. Yes, the proportion of sampled angles smaller than 15° is greater than 0.50.
B. Yes, the proportion of sampled angles smaller than 15° is not greater than 0.50.
C. No, the proportion of sampled angles smaller than 15° is greater than 0.50.
D. No, the proportion of sampled angles smaller than 15° is not greater than 0.50.
Answer: A. Yes, the proportion of sampled angles smaller than 15° is greater than 0.50.
Step-by-step explanation:
Given the data :
Class: _______ relative frequency
0−<5 __________ 0.179
5−<10 __________ 0.168
10−<15 _________ 0.174
15−<20 _________ 0.135
20−<30 _________0.193
30−<40 _________ 0.071
40−<60 _________ 0.051
60−<90 _________ 0.029
Evaluating the proportion of sampled angles less than 15°. This consist of the following classes :
Class: ________frequency
0−<5 __________ 0.179
5−<10 __________ 0.168
10−<15 _________ 0.174
Summing up the relative frequency values :
(0.179 + 0.168 + 0.174) = 0.521
0.521 * 100% = 52.1%
Hence, more than 50% of the sampled angles are smaller than 15°
7th grade math help me plzzzz
Answer:
B.
Step-by-step explanation:
Answer:
0.05 per ounce
Step-by-step explanation:
5.20 per 40 is 0.13 per ounce
whereas
2.70 per 15 is 0.18 per ounce
Check all true statements.
A. For all nonempty sets A, B, C, D, if A x B = C x D, then A = C and B = D.
B. For all sets A, B, the power set of the cartesian product of A and B is the cartesian product of the power sets of A and B. If A={1,2} and B={3} then A x B ={ {1,3}, {2,3} }.
C. The cartesian product has a cancellation property, i.e. if A x B = A x C for some sets A, B, C and A nonempty, then B = C. If A={1,2} and B={3} then A x B ={ (1,3), (2,3) }.
D. The cartesian product is symmetric, i.e. A x B = B x A for all sets A, B. For all sets A, B, the cardinality of A x B is the sum of the cardinalities of A and B.
E. The cartesian product is associative, i.e. (A x B) x C = A x (B x C) =for all sets A, B, C. Both sets are equal to A x B x C.
F. The cartesian product has a cancellation property, i.e. if A x B = A x C for some sets A, B, C, then B = C.
Step-by-step explanation:
the true statemnts underneath and are in bold letters
-.For all nonempty sets A, B, C, D, if A x B = C x D, then A = C and B = D.
This property is true
-The cartesian product has a cancellation property, i.e. if A x B = A x C for some sets A, B, C and A nonempty, then B = C.
This property is true
- If A={1,2} and B={3} then A x B ={ (1,3), (2,3) }.
if we have 2 non empty sets a and b if we want to get their cartesian product, it is defined as the set of all ordered pairs from a and b
we have A x B to be{(1,3)(2,3)}
therefore this is also true
What is the converse of the conditional statement?
If x is even, then x + 1 is odd.
A. If x is not even, then x + 1 is not odd.
B. lf x + 1 is odd, then x is even.
C. If x + 1 is not odd, then x is not even.
D. If x is even, then x + 1 is not odd.
Answer:
If x+1 is odd, then x is even B
Step-by-step explanation:
Conditional: If p, then q
Converse: If q, then p
p= x being even
q, x+1 being odd.
What is the slope of the line that passes through the points (1, 1) and (7, 5)?
Answer:
The slope of the line is
[tex] \frac{2}{3} [/tex]
to bake 100 of his favorite cookies, Mr.Wallis needs 350 grams of sugar. How many grams of sugar would he need to bake 10 cookies?
answer:35 grams
explication: because if he need 350 grams of sugar to make 100 cookies , we have to divide 350 by 100 so it gives 35
The number of grams of sugar would he need to bake 10 cookies will be 35 grams.
What are ratio and proportion?A ratio is a collection of ordered integers a and b represented as a/b, with b never equaling zero. A proportionate expression is one in which two items are equal.
To bake 100 of his favorite cookies, Mr.Wallis needs 350 grams of sugar.
Let x be the amount of sugar for 10 cookies.
The number of grams of sugar would he need to bake 10 cookies will be
x / 10 = 350 / 100
x / 10 = 3.5
x = 35 grams
The number of grams of sugar would he need to bake 10 cookies will be 35 grams.
More about the ratio and the proportion link is given below.
https://brainly.com/question/14335762
#SPJ2
Which set of ordered pairs does not represent a function?
\{(5, -6), (-1, -2), (2, -9), (-8, -2)\}{(5,−6),(−1,−2),(2,−9),(−8,−2)}
\{(-5, 7), (-4, -9), (-5, -4), (2, -6)\}{(−5,7),(−4,−9),(−5,−4),(2,−6)}
\{(-4, 2), (-2, 8), (-1, 6), (5, 6)\}{(−4,2),(−2,8),(−1,6),(5,6)}
\{(2, 2), (-4, 9), (9, -3), (-3, 2)\}{(2,2),(−4,9),(9,−3),(−3,2)}
Answer:
the 1st, 2nd, and 4th one because those ordered pairs, the y axis is the same . sooo thats what makes it a non function .
find each sum.
17+(-28
12+(-9)
-2+7
-14+(-10)
-9+(-2)
Answer:
-2834
Step-by-step explanation:
thats the answer
6 divided by the sum of x and 4 equals the quotient of 2 and the difference of x and 4
Answer:
6
Step-by-step explanation:
k bik k,k h
Round the numbers to the highest place value.
2 398-
56 254-
71 563-
33 021-
9 645-
Answer:
[tex]2398 = 2000[/tex]
[tex]56254 = 60000[/tex]
[tex]71563 = 70000[/tex]
[tex]33021 = 30000[/tex]
[tex]9645 = 10000[/tex]
Step-by-step explanation:
Given
[tex]2398[/tex]
[tex]56254[/tex]
[tex]71563[/tex]
[tex]33021[/tex]
[tex]9645[/tex]
Required
Round up to highest place value
[tex]2398[/tex]
Highest place value here is thousand.
So:
[tex]2398 = 2000[/tex], when approximated
[tex]56254[/tex]
Highest place value here is ten thousand.
So:
[tex]56254 = 60000[/tex], when approximated
[tex]71563[/tex]
Highest place value here is ten thousand.
So:
[tex]71563 = 70000[/tex] when approximated
[tex]33021[/tex]
Highest place value here is ten thousand.
So:
[tex]33021 = 30000[/tex] when approximated
[tex]9645[/tex]
Highest place value here is ten thousand.
So:
[tex]9645 = 10000[/tex] when approximated
Solve the system of equations 2x-4y=-2 and -x+8y=-23 by combining the equations.
Answer:
(−9,−4)
Step-by-step explanation:
I am 15 years old right now. How many years until i turn 18 years old?? I was born on May 9, 2005. If yoi answer this one i will give you brainly
y=12x^2-9x+4 does this have one two or no solution
Someone, please help me.
In the diagram below, lines x and y are parallel. What is the relationship between angle b and e? Write an equation if it help
Answer:
there is no relationship between the two angles if E switched with D then id say corresponding but theres not
Given a linear equation in the form y=mx+b, what are the values of the slope and y-intercept of the equation?(1 point) The slope is m, and the y-intercept is y. The slope is x, and the y-intercept is b. The slope is b, and the y-intercept is m. The slope is m, and the y-intercept is b.
Answer:
The slope is m, and the y-intercept is b.
Step-by-step explanation:
What ever is attached to the x is the slope. The y-intercept is the b because it has a 0 on the x axis and a number on the y axis.