In: Statistics and Probability
A marine biologist recorded the number of deaths of specific fish species from the last 10 years due to pollution in a specific area off the Pacific coast. She was curious to see if there was a trend. Identify the best mathematical model with its corresponding R2 value and tell whether it is a good model.
Year | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
---|---|---|---|---|---|---|---|---|---|---|
Deaths | 9 | 8 | 6 | 24 | 19 | 1 | 10 | 15 | 18 | 21 |
A. quadratic model, 0.176
Yes, 0.176 is very close to 0.
B. quadratic model, 0.176
No, 0.176 is a very low R2 value.
C. linear model, 0.163
No, 0.163 is a very low R2 value.
D. linear model, 0.163
Yes, 0.163 is very close to 0.
data
deaths | year | year^2 |
9 | 1 | 1 |
8 | 2 | 4 |
6 | 3 | 9 |
24 | 4 | 16 |
19 | 5 | 25 |
1 | 6 | 36 |
10 | 7 | 49 |
15 | 8 | 64 |
18 | 9 | 81 |
21 | 10 | 100 |
linear regression result
SUMMARY OUTPUT | |||||
Regression Statistics | |||||
Multiple R | 0.404158042 | ||||
R Square | 0.163343723 | ||||
Adjusted R Square | 0.058761689 | ||||
Standard Error | 7.179727352 | ||||
Observations | 10 | ||||
ANOVA | |||||
df | SS | MS | F | Significance F | |
Regression | 1 | 80.51212121 | 80.51212121 | 1.56187173 | 0.246712981 |
Residual | 8 | 412.3878788 | 51.54848485 | ||
Total | 9 | 492.9 | |||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | |
Intercept | 7.666666667 | 4.904687513 | 1.563130505 | 0.15664924 | -3.643563019 |
year | 0.987878788 | 0.790461966 | 1.249748667 | 0.246712981 | -0.834929774 |
quadratic regression result
SUMMARY OUTPUT | |||||
Regression Statistics | |||||
Multiple R | 0.419844848 | ||||
R Square | 0.176269696 | ||||
Adjusted R Square | -0.059081819 | ||||
Standard Error | 7.615929421 | ||||
Observations | 10 | ||||
ANOVA | |||||
df | SS | MS | F | Significance F | |
Regression | 2 | 86.88333333 | 43.44166667 | 0.748963507 | 0.507279896 |
Residual | 7 | 406.0166667 | 58.00238095 | ||
Total | 9 | 492.9 | |||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | |
Intercept | 10.08333333 | 8.957489994 | 1.125687368 | 0.297407108 | -11.09776474 |
year | -0.220454545 | 3.741025456 | -0.058928908 | 0.954655739 | -9.066574065 |
year^2 | 0.109848485 | 0.331440785 | 0.33142718 | 0.750023142 | -0.673884434 |
R^2 for linear model = 0.163
for quadratic model = 0.176
quadratic model ,0.176
0.176 is a very low , hence it is not a good model
option B) is correct