In: Math
Consider the following table summarizing the speed limit of a certain road and the number of accidents occurring on that road in January. Posted Speed Limit 52 50 43 36 21 22. Reported Number of Accidents 27 26 23 18 18 11. 1) Find the slope of the regression line predicting the number of accidents from the posted speed limit.Round to 3 decimal places. 2) Find the intercept of the regression line predicting the number of accidents from the posted speed limit. Round to 3 decimal places. 3) Predict the number of reported accidents for a posted speed limit of 25mph. Round to the nearest whole number.
Consider the following table summarizing the speed limit of a certain road and the number of accidents occurring on that road in January. Posted Speed Limit 52 50 43 36 21 22. Reported Number of Accidents 27 26 23 18 18 11.
Find the slope of the regression line predicting the number of accidents from the posted speed limit.Round to 3 decimal places.
Slope= 0.405
2) Find the intercept of the regression line predicting the number of accidents from the posted speed limit. Round to 3 decimal places.
Intercept=5.384
3) Predict the number of reported accidents for a posted speed limit of 25mph. Round to the nearest whole number.
The estimated regression line is number of accidents =5.384+0.405*speed limit
When speed limit is 25,
Predicted number of accidents =5.384+0.405*25=15.509
=16 ( rounded)
Excel Addon Megastat used.
Menu used: correlation/Regression ---- Regression Analysis
Regression Analysis |
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r² |
0.823 |
n |
6 |
||||
r |
0.907 |
k |
1 |
||||
Std. Error of Estimate |
2.832 |
Dep. Var. |
Number of Accidents |
||||
Regression output |
confidence interval |
||||||
variables |
coefficients |
std. error |
t (df=4) |
p-value |
95% lower |
95% upper |
|
Intercept |
a = |
5.384 |
|||||
Speed |
b = |
0.405 |
0.094 |
4.315 |
.0125 |
0.144 |
0.665 |
ANOVA table |
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Source |
SS |
df |
MS |
F |
p-value |
||
Regression |
149.409 |
1 |
149.409 |
18.62 |
.0125 |
||
Residual |
32.091 |
4 |
8.023 |
||||
Total |
181.500 |
5 |
|||||
Predicted values for: Number of Accidents |
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95% Confidence Interval |
95% Prediction Interval |
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Speed |
Predicted |
lower |
upper |
lower |
upper |
Leverage |
|
25 |
15.51 |
10.96 |
20.05 |
6.42 |
24.59 |
0.334 |