answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
iogann1982 [59]
2 years ago
15

An observational study found that the amount of sleep an employee gets each night is associated with job performance. The correl

ation coefficient was found to be r=0.86. A reader of the study concluded that more sleep causes employees to perform better. Why is such a conclusion not correct?
A)The correlation value should equal 1 for such a conclusion.
B)The correlation value should be negative for such a conclusion.
C)The sample was not representative of the population.
D) Causation cannot be determined from an observational study.
E) The correlation value implies that less than 75% of the variability in job performance can be explained by sleep.
Mathematics
1 answer:
Elina [12.6K]2 years ago
6 0

Answer:

The correct option is D.) Causation cannot be determined from an observational study.

Step-by-step explanation:

The conclusion is not correct because

D.) Causation cannot be determined from an observational study.

Causation determined from an observational study is speculative and cannot be confirmed without data from a real experiment.

You might be interested in
We want to estimate the population mean within 5, with a 99% level of confidence. the population standard deviation is estimated
pashok25 [27]
A sample size of 60 is required.

We use the formula
n=(\frac{z*\sigma}{E})^2

We first find the z-score associated with this level of confidence:
Convert 99% to a decimal:  99/100 = 0.99
Subtract from 1:  1-0.99 = 0.01
Divide by 2:  0.01/2 = 0.005
Subtract from 1:  1-0.005 = 0.995

Using a z-table (http://www.z-table.com) we see that this value is equally distant from 2.57 and 2.58; therefore we will use 2.575:

n=(\frac{15(2.575)}{5})^2=59.68\approx60
3 0
2 years ago
The picture shows the footprints of a man walking. The pace length P is the distance between the rear of two consecutive footpri
Rina8888 [55]

Bernard’s walking speed is 140 meters per minute

Bernard’s walking speed is 8.4 kilometers per hour

Step-by-step explanation:

The pace length P is the distance between the rear of two consecutive footprints

The formula, n P = 140, gives an approximate relationship between n and P where,

  • n = number of steps per minute
  • P = pace length in meters
  • Bernard knows his pace length is 0.80 meters
  • The formula applies to Bernard’s walking

We need to calculate Bernard’s walking speed in meters per minute and in kilometers per hour

∵ n = number of steps per minute

∴ n unit is number / minute

∵ P = pace length in meters

∴ P unit is meter

- That means n P unit is meters/minute

∴ n P represents the speed in meters per second

∵ The formula applies to Bernard’s walking

∵ His pace length is 0.80 meters

∵ n P = 140

∴ n(0.8) = 140

- Divide both sides by 0.8

∴ n = 175

- That means he moves 175 steps per minute

∵ The distance he walks in minute = 175 × 0.8 = 140 meters/minute

∴ His speed is 140 meters per minute

Bernard’s walking speed is 140 meters per minute

∵ 1 km = 1000 m

∵ 1 hour = 60 minutes

- Divide the meters by 1000 and the minute by 60 to change

   from meters per minute to kilometers per hour

∴ His walking speed = \frac{140}{1000} ÷ \frac{1}{60}

- Change ÷ to × and reciprocal the fraction after the division sign

∴ His walking speed =  \frac{140}{1000} × \frac{60}{1} = 8.4 km/h

Bernard’s walking speed is 8.4 kilometers per hour

Learn more:

You can learn more about the speed in brainly.com/question/5461619

#LearnwithBrainly

7 0
2 years ago
Two random samples were taken to determine how often people in a community listen to the local radio station each month. The fir
leonid [27]

Answer:

The answers to this question are 1,2,4,6. Hope this helps you

Step-by-step explanation:

3 0
2 years ago
Harry and Helen are married, filing jointly. Their combined taxable income is $65,922. Every week, a total of $187 is withheld f
makkiz [27]

Answer:

Your correct answer is d. Harry and Helen will receive a refund of $555. explain please

Step-by-step explanation:

Hope this helps :) -Mark Brainiest Please :)

4 0
2 years ago
Read 2 more answers
How does the exponent of each power of ten correspond with placing a decimal
Rom4ik [11]
You would then move the decimal how many places you were given
3 0
2 years ago
Other questions:
  • Dr. Black is standing 13 feet from a streetlamp. The lamp is making his shadow 9 feet long. He estimates that the angle of eleva
    10·2 answers
  • you pick a number between 1,000 and 5,000 then you flip a coin identify if the two events are independent or dependent explain
    10·2 answers
  • I have a limited time please help ;-;
    9·2 answers
  • Esmerelda rents a car from a company that rents cars by the hour. She has to pay an initial fee of $52, and then they charge her
    10·1 answer
  • The median home price in the United States over the period 2003-2011 can be approximated by P(t) = −5t2 + 75t − 30 thousand doll
    5·1 answer
  • Describe the sample space for each of these experiments (a) A coin is tossed and a single die is rolled. (b) A paper cup is toss
    15·1 answer
  • The height of a stuntperson jumping off a building that is 20 m high is modeled by the equation h = 20 -57, where t is the time
    6·1 answer
  • Circular tracts of land with diameters 900 meters, 700 meters and 600 meters are tangent to each other externally. There are hou
    15·1 answer
  • Two submersibles, one red and one blue, started rising toward the surface at the same time. They each rose at a constant speed.
    14·1 answer
  • By coincidence, Kimberly’s Paint Supplies sold equal quantities of two paint colors yesterday: yellow and blue. All yellow paint
    8·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!