What is the relationship between the amount of time statistics students study per week and their final exam scores? The results of the survey are shown below.   Time 0 5 4 4 14 16 7 5 2 Score 42 55 59 59 84 83 59 73 66   Find the correlation coefficient:  r=r=    Round to 2 decimal places. The null and alternative hypotheses for correlation are: H0:H0: ? μ ρ r  == 0 H1:H1: ? ρ μ r   ≠≠ 0     The p-value is:    (Round to four decimal places)

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
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Chapter4: Equations Of Linear Functions
Section4.5: Correlation And Causation
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What is the relationship between the amount of time statistics students study per week and their final exam scores? The results of the survey are shown below.

 

Time 0 5 4 4 14 16 7 5 2
Score 42 55 59 59 84 83 59 73 66

 

  1. Find the correlation coefficient:  r=r=    Round to 2 decimal places.
  2. The null and alternative hypotheses for correlation are:
    H0:H0: ? μ ρ r  == 0
    H1:H1: ? ρ μ r   ≠≠ 0    
    The p-value is:    (Round to four decimal places)
  3. Use a level of significance of α=0.05α=0.05 to state the conclusion of the hypothesis test in the context of the study.
    • There is statistically significant evidence to conclude that a student who spends more time studying will score higher on the final exam than a student who spends less time studying.
    • There is statistically significant evidence to conclude that there is a correlation between the time spent studying and the score on the final exam. Thus, the regression line is useful.
    • There is statistically insignificant evidence to conclude that there is a correlation between the time spent studying and the score on the final exam. Thus, the use of the regression line is not appropriate.
    • There is statistically insignificant evidence to conclude that a student who spends more time studying will score higher on the final exam than a student who spends less time studying.
  4.  r2r2 =  (Round to two decimal places)  
  5.  Interpret r2r2 :  
    • Given any group that spends a fixed amount of time studying per week, 71% of all of those students will receive the predicted score on the final exam.
    • There is a 71% chance that the regression line will be a good predictor for the final exam score based on the time spent studying.
    • 71% of all students will receive the average score on the final exam.
    • There is a large variation in the final exam scores that students receive, but if you only look at students who spend a fixed amount of time studying per week, this variation on average is reduced by 71%.
  6. The equation of the linear regression line is:   
    ˆyy^ =  + xx   (Please show your answers to two decimal places)  
  7. Use the model to predict the final exam score for a student who spends 10 hours per week studying.
    Final exam score =  (Please round your answer to the nearest whole number.)  
  8. Interpret the slope of the regression line in the context of the question:  
    • The slope has no practical meaning since you cannot predict what any individual student will score on the final.
    • As x goes up, y goes up.
    • For every additional hour per week students spend studying, they tend to score on averge 2.16 higher on the final exam.
  9. Interpret the y-intercept in the context of the question:
    • The y-intercept has no practical meaning for this study.
    • The best prediction for a student who doesn't study at all is that the student will score 51 on the final exam.
    • The average final exam score is predicted to be 51.
    • If a student does not study at all, then that student will score 51 on the final exam.
Expert Solution
Step 1

Hello! As you have posted more than 3 sub parts, we are answering the first 3 sub-parts.  In case you require the unanswered parts also, kindly re-post that parts separately.

1.

Correlation between Time score is,

r=0.84, from the excel function, =CORREL(A2:A10,B2:B10)

2.

Null Hypothesis:

H0:ρ=0

Alternative Hypothesis:

H1:ρ0

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