An experiment was conducted to measure the reaction time in seconds when differe

Question

An experiment was conducted to measure the reaction time in seconds when different amounts of catalyst are added to accelerate a chemical reaction. It is desired to predict the reaction time. Selected SPSS output is given below Model Summary Adjusted Std. Error of R SquareRSquare the Estimate 2.16025 Model 981a 963 950 a. Predictors: (Constant), x ANUVA Sum of Model df Mean Square 360.000 4.667 Squares Si Regression Residual Total 77.143 003a 360.000 14.000 374.000 3 4 a. Predictors: (Constant), x b. Dependent Variable: y Coefficients* Unstandardized Coefficients Standardized Coefficients Beta Std. Error 2.266 683 Model Si (Constant)57.000 -6.000 25.158 8.783 003 a. Dependent Variable: y Please show all your work and answers in the spaces provided a) State the equation of the least-squares line for predicting the reaction time (in seconds) b) Interpret the slope in the context of this problem. (If you do not know what the slope value is use the value 4) c) SPSS always reports the correlation coefficient to be positive. (If it truly is negative then SPSS shows the absolute value). Explain how would we should use the intercept &/or slope to determine whether the reported value of the correlation coefficient should be negative or positive d) To the extent possible, assess the fit of the regression line. e) Predict the reaction time when 10 units of catalyst are added

Explanation / Answer

SolutionA:

reaction_time=57-6(units of catalyst)

Y intercept=57

slope=-6

SolutionB:

slope=-6

change in Meauring time/change in units of catalyst=-6

for a unit of catalyst incraese,reaction time decreases by 57 seconds

Solutionc:

r=-0.963

but this might not be true

since slope of regression line is negative ,

correlation coefficient should be negative

it should be r=-0.981

slope=r(Sy/Sx)

so r =-0.983

Solutiond:

From output R sq=0.963

that is

0.963*100=96.3%

that is 96.3% varaition in reaction time is explained by units of catalyst.
Good model

We can use for predicting the reaction time given units of catalyst.

Solutione:

given x=10

reaction_time=57-6(units of catalyst)

=57-6(10)

=-3 seconds

time=3 seconds

  

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.