A chemical engineer discovered that by adding different amounts of an additive to gasoline, he could reduce the amount of nitrous oxides (NOx) from a car engine. A specified amount was added to one gallon of gasoline and the total amount of NOx in the exhaust was collected. Assume, in suitable units, that the data is: amount of additive 1 2 3 4 5 Nox 19 17 14 13 12 a) Obtain the least squares fit, of a straight line, for the amount of NOx b) Test whether or not the slope is β = 0. Consider a significance level of 0.01. c) Provide a 99% confidence interval for the mean value of NOx when the amount of additive is 9.
Correlation
Correlation defines a relationship between two independent variables. It tells the degree to which variables move in relation to each other. When two sets of data are related to each other, there is a correlation between them.
Linear Correlation
A correlation is used to determine the relationships between numerical and categorical variables. In other words, it is an indicator of how things are connected to one another. The correlation analysis is the study of how variables are related.
Regression Analysis
Regression analysis is a statistical method in which it estimates the relationship between a dependent variable and one or more independent variable. In simple terms dependent variable is called as outcome variable and independent variable is called as predictors. Regression analysis is one of the methods to find the trends in data. The independent variable used in Regression analysis is named Predictor variable. It offers data of an associated dependent variable regarding a particular outcome.
A chemical engineer discovered that by adding different amounts of an additive to gasoline, he could reduce the amount of nitrous oxides (NOx) from a car engine. A specified amount was added to one gallon of gasoline and the total amount of NOx in the exhaust was collected. Assume, in suitable units, that the data is:
| amount of additive | 1 | 2 | 3 | 4 | 5 |
| Nox | 19 | 17 | 14 | 13 | 12 |
a) Obtain the least squares fit, of a straight line, for the amount of NOx
b) Test whether or not the slope is β = 0. Consider a significance level of 0.01.
c) Provide a 99% confidence interval for the mean value of NOx when the amount of additive is 9.
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