Because
r is significant and the scatter plot shows a linear trend, the regression line can be used to predict final exam scores.
Method 2: using a table of critical values to make a decision
The
95% Critical Values of the Sample Correlation Coefficient Table can be used to give you a good idea of whether the computed value of
is significant or not . Compare
r to the appropriate critical value in the table. If
r is not between the positive and negative critical values, then the correlation coefficient is significant. If
r is significant, then you may want to use the line for prediction.
Suppose you computed
r = 0.801 using
n = 10 data points.
df =
n - 2 = 10 - 2 = 8. The critical values associated with
df = 8 are -0.632 and + 0.632. If
r <negative critical value or
r >positive critical value, then
r issignificant. Since
r = 0.801 and 0.801>0.632,
r is significant and the line may be usedfor prediction. If you view this example on a number line, it will help you.
r is not significant between -0.632 and +0.632.
r = 0.801>+0.632. Therefore,
r is significant.
For a given line of best fit, you computed that
r = 0.6501 using
n = 12 data points and the critical value is 0.576. Can the line be used for prediction? Why or why not?
If the scatter plot looks linear then, yes, the line can be used for prediction, because
r >the positive critical value.
Suppose you computed
r = –0.624 with 14 data points.
df = 14 – 2 = 12. The critical values are –0.532 and 0.532. Since –0.624<–0.532,
r is significant and the line can be used for prediction
For a given line of best fit, you compute that
r = 0.5204 using
n = 9 data points, and the critical value is 0.666. Can the line be used for prediction? Why or why not?
No, the line cannot be used for prediction, because
r <the positive critical value.
Suppose you computed
r = 0.776 and
n = 6.
df = 6 – 2 = 4. The critical values are –0.811 and 0.811. Since –0.811<0.776<0.811,
r is not significant, and the line should not be used for prediction.
-0.811<
r = 0.776<0.811. Therefore,
r is not significant.
For a given line of best fit, you compute that
r = –0.7204 using
n = 8 data points, and the critical value is = 0.707. Can the line be used for prediction? Why or why not?
Yes, the line can be used for prediction, because r<the negative critical value.
Third-exam vs final-exam example: critical value method
Consider the
third exam/final exam example .
The line of best fit is:
ŷ = –173.51+4.83
x with
r = 0.6631 and there are
n = 11 data points. Can the regression line be used for prediction?
Given a third-exam score (
x value), can we use the line to predict the final exam score (predicted
y value)?
H
0 :
ρ = 0
H
a :
ρ ≠ 0
α = 0.05
Use the "95% Critical Value" table for
r with
df =
n – 2 = 11 – 2 = 9.
The critical values are –0.602 and +0.602
Since 0.6631>0.602,
r is significant.
Decision: Reject the null hypothesis.
Conclusion:There is sufficient evidence to conclude that there is a significant linear relationship between the third exam score (
x ) and the final exam score (
y ) because the correlation coefficient is significantly different from zero.
Questions & Answers
Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you.
Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
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