I need the complete working solutions and accurate answers to this question. Tha

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I need the complete working solutions and accurate answers to this question. Thank you.

(8 pts.) 7. BONUS To keep golf courses attractive in the arid southwest, groundskeepers carefully monitor salt content in water used for irrigation. It is believed that high salt concentration can damage plants and grass. A random sample of golf courses in the southwest was obtained and a sample of water used for irrigating was obtained for each. The following variables were measured for each water sample: dissolved salt (y, dS/m), total dissolved solids (x,, mg/L), sodium, calcium magnesium, and bicarbonate (x2, X3, X4, and X5, all in milliequiv-alents/liter). The following are the results from SAS Analysis of Variance Sum of M ean DF Squares Square F Value Pr> Source Model Error Corrected Total 9 6.50100 5 6.470931.29419 172.18 t 1 0.05103 0.17107 0.30 0.7803 10.00279 0.00047413 -5.88 0.0042 1 0.32472 0.03398 9.56 0.0007 1 0.27769 0.04089 6.79 0.0025 (1 pt.) a) What is the formula for the estimated regression line? (6 pts.) b) Is the overall regression significant at a significance level of 0.01? Hint: Perform an F test at a significance level of 0.01 (1 pt.) c) Which of the variables are linearly associated with the salt content in water assuming that the rest of the variables are in the model? You may assume a significance level of 0.01 You do not have to perform any significance tests but you have to explain how you arrive at your answer Additional Problems: 12.143

Explanation / Answer

a)

Reqression line

Dissoved salt = b1*solids + b2*sodium + b3*calcium + b4*magnesium + b5*bicorbonate + b0

=> Y = 0.05103 - 0.00279x1 + 0.32472x2 + 0.27769x3 + 0.2188x4 - 0.10288x5

b)

H0 : Regression model is not significant

H1 : Regression model is significant

Decision rule : if p value < 0.01, regression model is significant

Actual decision : From the given SAS output, p value = 0.000 < 0.01, Reject H0

Conclusion : Given regression model is significant

c) The following variables are linearly associated with dissovled salt

the variables are significant(solids, sodium, calcium and magnesium)

since p values of all the variables except bicarbonate < 0.01

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