An analyst working at production plant is asked to estimate the price of a chemical that is used in their production process. The chemical can be purchased from different suppliers. There are various attributes that quantify the quality of the particular chemical, and which may have an influence on its price. The analyst developed a linear regression model based these quality attributes in order to predict the price of the chemical. The linear regression modelling produced the following results:

Attribute	Coefficient	Std. Error	Std. Coefficient	Tolerance	p-Value
Density	5.383	2.201	0.549	0.362	0.015
Impurities	- 0.946	0.103	-0.338	1.000	0.0
Reactive efficiency	0.008	0.263	0.001	0.998	0.977
Packaged weight	-0.665	2.139	-0.070	0.371	0.756
(Intercept)	4516.427	63.806	?	?	0.0

1. Write the regression equation for this model.

2 Explain which attribute(s) do not play a statistically significant role in the above regression model at the 95% confidence level. Justify your answer.

3 Explain which attribute(s) have a high likelihood of multi-collinearity in the above regression model. Justify your answer.