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0.933 Previous Answers trostal8 10 JE 032. My Notes The index of biotic integrit

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Question

0.933 Previous Answers trostal8 10 JE 032. My Notes The index of biotic integrity (IBI) is a measure of the water quality in streams. IBI and land-use measures for a collection of streams in the Ozark Highland ecoregion of Arkansas were collected as part of a study. The data data226.dat gives the data for IBI and the area of the watershed in square kilometers for streams in the original sample with area less than or equal to 70km (a) Use numerical and graphical methods to describe the variable IB Do the same for area. (Round your answers for X to two decimal places and your answers for s to three decimal places b) Run the simple linear regression and summarize the results, (Let x- area and y BI, Round your slope, intercept, and rto three decimal places. Round Fto two decimal places and your P-value to four decimal places.

Explanation / Answer

Answer:

a).

IBI

Mean=62.08    sd=20.184

Area

Mean=28.29   sd=17.714

b).

y=49.087+0.459*x

F=9.12

P=0.0041

r=0.403

Regression Analysis

0.163

n

49

r

0.403

k

1

Std. Error

18.666

Dep. Var.

ibi

ANOVA table

Source

SS

df

MS

F

p-value

Regression

3,179.1544

1  

3,179.1544

9.12

.0041

Residual

16,376.5191

47  

348.4366

Total

19,555.6735

48  

Regression output

confidence interval

variables

coefficients

std. error

   t (df=47)

p-value

95% lower

95% upper

Intercept

49.0865

5.0616

9.698

8.54E-13

38.9039

59.2691

area

0.4594

0.1521

3.021

.0041

0.1534

0.7654

Regression Analysis

0.163

n

49

r

0.403

k

1

Std. Error

18.666

Dep. Var.

ibi

ANOVA table

Source

SS

df

MS

F

p-value

Regression

3,179.1544

1  

3,179.1544

9.12

.0041

Residual

16,376.5191

47  

348.4366

Total

19,555.6735

48  

Regression output

confidence interval

variables

coefficients

std. error

   t (df=47)

p-value

95% lower

95% upper

Intercept

49.0865

5.0616

9.698

8.54E-13

38.9039

59.2691

area

0.4594

0.1521

3.021

.0041

0.1534

0.7654