In: Statistics and Probability
Consider the following data on price ($) and the overall score for six stereo headphones tested by a certain magazine. The overall score is based on sound quality and effectiveness of ambient noise reduction. Scores range from 0 (lowest) to 100 (highest).
Brand | Price ($) | Score |
---|---|---|
A | 180 | 76 |
B | 150 | 69 |
C | 95 | 59 |
D | 70 | 56 |
E | 70 | 40 |
F | 35 | 24 |
(a)
The estimated regression equation for this data is
ŷ = 21.926 + 0.321x,
where x = price ($) and y = overall score. Does the t test indicate a significant relationship between price and the overall score? Use α = 0.05.
State the null and alternative hypotheses.
H0: β1 = 0
Ha: β1 ≠
0H0: β1 ≠ 0
Ha: β1 =
0 H0:
β0 = 0
Ha: β0 ≠
0H0: β1 ≥ 0
Ha: β1 <
0H0: β0 ≠ 0
Ha: β0 = 0
Find the value of the test statistic. (Round your answer to three decimal places.)
Find the p-value. (Round your answer to four decimal places.)
p-value =
What is your conclusion?
Reject H0. We cannot conclude that the relationship between price ($) and overall score is significant.Do not reject H0. We cannot conclude that the relationship between price ($) and overall score is significant. Do not reject H0. We conclude that the relationship between price ($) and overall score is significant.Reject H0. We conclude that the relationship between price ($) and overall score is significant.
(b)
Test for a significant relationship using the F test. Use α = 0.05.
State the null and alternative hypotheses.
H0: β0 ≠ 0
Ha: β0 =
0H0: β1 = 0
Ha: β1 ≠
0 H0:
β0 = 0
Ha: β0 ≠
0H0: β1 ≠ 0
Ha: β1 =
0H0: β1 ≥ 0
Ha: β1 < 0
Find the value of the test statistic. (Round your answer to two decimal places.)
Find the p-value. (Round your answer to three decimal places.)
p-value =
What is your conclusion?
Do not reject H0. We conclude that the relationship between price ($) and overall score is significant.Do not reject H0. We cannot conclude that the relationship between price ($) and overall score is significant. Reject H0. We conclude that the relationship between price ($) and overall score is significant.Reject H0. We cannot conclude that the relationship between price ($) and overall score is significant.
(c)
Show the ANOVA table for these data. (Round your p-value to three decimal places and all other values to two decimal places.)
Source of Variation |
Sum of Squares |
Degrees of Freedom |
Mean Square |
F | p-value |
---|---|---|---|---|---|
Regression | |||||
Error | |||||
Total |
Using Excel<data<megastst<correlation/regression<regression
Here is the output:
Regression Analysis | ||||||
r² | 0.839 | |||||
r | 0.916 | |||||
Std. Error | 8.603 | |||||
n | 6 | |||||
k | 1 | |||||
Dep. Var. | Score | |||||
ANOVA table | ||||||
Source | SS | df | MS | F | p-value | |
Regression | 1,537.9281 | 1 | 1,537.9281 | 20.78 | .0104 | |
Residual | 296.0719 | 4 | 74.0180 | |||
Total | 1,834.0000 | 5 | ||||
Regression output | confidence interval | |||||
variables | coefficients | std. error | t (df=4) | p-value | 95% lower | 95% upper |
Intercept | 21.9264 | 7.86 | 2.79 | 0.05 | 0.09 | 43.76 |
Price ($) | 0.3207 | 0.0704 | 4.558 | .0104 | 0.1254 | 0.5161 |
a)
null hypothesis:Ho: | β1 | = | 0 | |
Alternate Hypothesis: Ha: | β1 | ≠ | 0 |
Test Staistic= 4.558
P value= 0.0104
Since p value <alpha ( Reject null hypothesis)
Conclusion
Reject H0. We conclude that the relationship between price ($) and overall score is significant.
b)
null hypothesis: | β1 | = | 0 | |
Alternate Hypothesis: | β1 | ≠ | 0 |
test statistic F =20.78
p value =0.0104
Reject H0. We conclude that the relationship between price ($) and the overall score is significant
c)
ANOVA table | |||||
Source | Sum of squares SS | df | MS | F | p-value |
Regression | 1,537.9281 | 1 | 1,537.9281 | 20.78 | .0104 |
Residual | 296.0719 | 4 | 74.0180 | ||
Total | 1,834.0000 | 5 |
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