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.

Answers

Answer 1

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


Related Questions

shopkeeper sells one machine for 990 re at a profit of 10% and another machine for 1960 at a loss of 2%

Answers

Complete question :

shopkeeper sells one machine for 990 re at a profit of 10% and another machine for 1960 at a loss of 2%. What is his gain or loss percent

Answer:

1.72%

Step-by-step explanation:

Given that :

MACHINE 1:

Sales price = 990

Profit percent = 10%

The cost price of the machine (x) :

10% profit of x :

(100 + 10)% of x = 990

110% of x = 990

1.1x = 990

x = 990/1.1

x = 900

MACHINE 2:

Sales price = 1960

Loss on sale = 2%

Cost price (x) :

(100 - 2)% of x = 1960

98% x = 1960

0.98x = 1960

x = 1960/0.98

x = 2000

Total amount realized from sale = (990 + 1960) = 2950

Total cost of production = (2000 + 900) = 2900

Profit Made = (2950 - 2900) = 50

% profit:

(Profit / cost of production) * 100

(50 / 2900) * 100%

0.0172413 * 100%

profit % = 1.72

The profit made is 50

Cost price of first machine will be:

= 100/(100 + 10) × 990

= 100/110 × 990

= 100 × 9

= 900

Cost price for second machine will be:

= (100 - 2) × x = 1960

= 98% × x = 1960

= 0.98x = 1960

x = 1960/0.98.

x = 2000

The total cost price = 900 + 2000 = 2900

Total selling price = 990 + 1960 = 2950

Therefore, profit will be:

= Selling price - Cost price .

= 2950 - 2900

= 50

Read related link on:

https://brainly.com/question/17698813

4x^3+52x^2+144x
solve by factoring

Answers

Answer:

4x(x^2 + 13x + 36)

Step-by-step explanation:

Multipy through to get the original value

Taylor can clean pools at a constant rate of 25 pools per hour. What is the ratio of pools to hours?

Answers

Answer:

25:1

Step-by-step explanation:

Pools:hours25:1

I hope this helps!

Answer:

2:6

Step-by-step explanation:

fist eufhuh rhbgr ncv u;hkjfn.jfmncmghlwirgihu

Write the equation of each line described in slope-intercept form (y = mx + b) with a slope of -6 and x-intercept of 4. (4,0)

Answers

Answer:

ill give u the answer if u do 73 divided by 2628

Step-by-step explanation:

Harriet paid $349.65 for 7 fruit trees. If each of the trees cost the same, what is the cost for one tree?

Answers

Answer:

$49.95

Step-by-step explanation:

Since each tree costs the same, we can find the individual cost by dividing the total cost by the number of trees:

349.65/7

= 49.95

So, the cost of one tree is $49.95

What is the inequality solution for y+2<4

Answers

Answer:

y<2

Step-by-step explanation:

Subtract 2 on both sides

Answer:

y<2

Step-by-step explanation:

find the sum of (3a+7)+(a−1)

Answers

Answer:

[tex] \huge{ \bold{ \boxed{ \text{4a + 6}}}}[/tex]

Step-by-step explanation:

[tex] \text{ (3a + 7) + (a - 1)}[/tex]

In addition , sign of each term in the expression remains unchanged. So, Remove the unnecessary brackets.

[tex] \text{⇢ \: 3a + 7 + a - 1}[/tex]

Combine like terms. Like terms are those which have the same base. Only coefficients of like terms can be added or subtracted.

[tex] \text{⇢ \: 3a + a + 7 - 1}[/tex]

[tex] \text{⇢ \boxed{ \text{4a + 6}}}[/tex]

And we're done! :D

Hope I helped!

Best regards! :D

~TheAnimeGirl

Jenny & Natasha are working on a problem together: Solve x / 3 + 8 = −2. Natasha thinks the first step is to multiply by 3. Jenny explains that this is not the most efficient way to solve. Explain who is correct & justify your reasoning.

Answers

Answer:

−2x3

Step-by-step explanation:

i sloved the equation then mulitipilied by 3

Felipe has a flower bed

Answers

Answer:

man thats cool

Step-by-step explanation:

LoL guess Pelipe is happy

In a class of 40 students, 26 are girls and 14 are boys. What is the ratio of girls to boys? Group of answer choices

14:26
14:40
26:40
26:14

Answers

26:14 is the ratio of the girls and boys

Answer:

26:14

Step-by-step explanation:

It ask for girls first and there are 26, then boys which is 14. So the ratio would be 26:14.

Hope this helps

Pleaseeeeeeee, help meeeeeeee

Answers

kikaksyvjabsjxjjcjallalalalakjdiloveyouhahahahjss

what bro bye bro that’s weird bro

angle 4 and angle 5 are ??? angles will mark brainiest ​

Answers

Answer:

alternate interior

Step-by-step explanation:

alternate interior angles are congruent if and only lines are parallel.

What is 5 to the second power

Answers

it is basically asking what is 5 squared which is 25!!

Answer:

25

Step-by-step explanation:

5 times 5

5x5=25

hope this helps

3 of 5
Simplify as far as possible without a calculator.
33(272+273)

Answers

Answer:

17,985

Step-by-step explanation:

33(545)= 17,985

Solve
8(12 - k) = 3(k + 21)
Please help! I am confused with some signs.​

Answers

Answer: k = 3

Step-by-step explanation:

U first expand

96 - 8k = 3k + 63

Then u add 8k from both sides

96 = 3k + 63 + 8k

then u simplify

3k + 63 + 8k to 11k + 63

then u subtract 63 from both sides

96 = 11k + 63

Then u simplify 96 - 63 to 33

33 = 11k

Then u divide both sides by 11

33/11 = k

then u simplify 33/11 to 3

3 = k

and last u switch the sides

k = 3

Which statement best describes the rate of change for this situation

Answers

50 miles per hour because you can see that at 200 miles the time is 4 so if you divide 200/4 you get 50

What is the five-number summary for this data set?
4,6, 10, 13, 18, 28, 34, 46, 50, 58
Assume the numbers in each answer choice are listed in this order: min, Q1,
median, Q3, max.

Answers

Answer:

4, 10, 23, 46, 58

Step-by-step explanation:

this is easy stuff bro, did u rlly have to look this up

Arrange the three numbers shown in order from least to greatest.
1. 0.67
2. 6/9
3. 6.7%

Answers

Answer:1. 6/9 2. 0.69 3. 6.7

Step-by-step explanation:i think this is correct

Answer:

It is: 6.7%, 6/9, 0.67.

Step-by-step explanation:

Convert all your numbers to decimals.

6.7% = 0.067

6/9 = 0.66... (repeating decimal)

0.67 = 0.67 (already a decimal)

Line the decimals up to make them fair to compare then order them from least - greatest.

Find DF
D
20
E 10 F
DF =

Answers

Answer:

30

Step-by-step explanation:

it is right

it’s 30!

bc DE is 20 and EF is 10, if DF is the entire segment, then you would add 20 & 10, to get 30.

Write the inequality given below.

Eight less than 2 times a number is more than 12. ​

Answers

Answer:

Step-by-step explanation:

8-2x>12

will be nice if you give me brainlies.Good luck!

A remote control car travels at a rate of 10 feet per second. How many inches per second is this? (1 feet = 12 inches)

Answers

10 feet would be 120 inches

Why can't a whole number be irrational? Please dumb it down for me

Answers

Answer and Step-by-step explanation:

A whole number isn't irrational because it is a whole number. Confused? Most likely.

A whole number is any of the numbers {0, 1, 2, 3, ...} etc. There is no fractional or decimal part. And no negatives. Example: 5, 49 and 980 are all whole numbers.

An Irrational Number is a real number that cannot be written as a simple fraction. Irrational means not Rational. The irrational numbers are all the real numbers which are not rational numbers. That is, irrational numbers cannot be expressed as the ratio of two integers.

These are both real numbers because they don't go through the 4th wall (of science/math)

Imaginary numbers would use i.

Which statement is TRUE about
V131
?
A) It lies between 12 and 13 on a number line.
B) It lies between 11 and 12 on a number line.
C) It lies between 10 and 11 on a number line.
D) It lies between 9 and 10 on a number line.

Answers

Answer:

I think the answer is B It lies between 11 and 12

Step-by-step explanation:

2/5 - 4 (5.4) solve​

Answers

Answer: -106/5= −21.2

Step-by-step explanation:     Adding fractions which have a common denominator

Combine the numerators together, put the sum or difference over the common denominator then reduce to lowest terms if possible:

2 - (108)/5 = -106/5

A consumer wanted to compare two types of battery storage. One type is refrigerated and the other is room temperature. It is a common belief that refrigerated batteries last longer. This belief is tested by placing 10 fully charged batteries into each type of storage and then measuring the percentage of charge remaining after thirty days. A coin tip was used to determine which type of storage each battery would be placed in first. Results indicated that there was no difference in the two types of storage Complete parts (a) through in below.
What type of experimental design is this?
A) Matched pairs design
B) Completely randomized design
C) Randomized block design
D) Case-control study

Answers

Answer:

A) Matched pairs design

Step-by-step explanation:

In experimental design, the match pairs experimental design is one that often involves only two treatment conditions; which in this case are the 'refrigerated and the room temperature battery storage types'.

Thus, these two treatment conditions form a matched pair because we are told that 10 fully charged batteries are placed into each type of storage.

What is 797 rounded to the nearest ten?

Answers

Answer: 800

Step-by-step explanation:

Graph the line passing through (4,−1) whose slope is m=43.

Answers

I can’t really graph it, but I will tell you the points on the graph. The points are (5,42). Hope this helped :D

Serena charges $6.50 an hour to walk dogs. She worked 5 hours last week and 9.5 hours this week. How much did she make altogether in the last two weeks?

Answers

Answer:

She made 91 dollars

Step-by-step explanation:

6.50 times 5 = 32.5

6.50 times 9 =58.5

58.5+32.5=91

Answer:

Your answer is $91.00.

Step-by-step explanation:

6.50 * 5 = 32.5

6.50 * 9 = 58.5

             =  91

Hope this helps!

A
B
C
D

Thanks for helping me

Answers

Oh shoot I forgot it’s in the back of my head I’ll lyk when I remember

1 1/4 packages of beads to make 10 bracelets. he wants to make 25 bracelets. how many packages of beads will he use

Answers

Answer:

55/8

Step-by-step explanation:

If 11/4 packages of beads are used to make 10 bracelets;

Hence the number of packages of beads that would be used to make 25 bracelets = (11/4 × 25)/10 = 55/8 packages of beads.

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