Which of the following is NOT an assumption for the simple linear regression model?
A) The individual error terms are statistically independent.
B) The distribution of the error terms will be skewed left or right depending on the shape of the dependent variable.
C) The error terms have equal variances for all values of the independent variable.
D) The mean of the dependent variable value for all levels of x can be connected by a straight line.
Q. 2It is entirely possible for the R-chart to show that a process is in statistical control and the -chart to show that the same process is out of control.
Indicate whether the statement is true or false
Q. 3If a time-series plot indicates that the data do not appear to exhibit a trend, then a double exponential smoothing model would likely be the most appropriate to use rather than simple exponential smoothing model.
Indicate whether the statement is true or false
Q. 4Which of the following is not an indication of potential multicollinearity problems?
A) The sign on the standard error of the estimate is positive.
B) A sign on a regression slope coefficient is negative when the sign on the correlation coefficient was positive.
C) The standard error of the estimate increases when a variable enters the model in the presence of other independent variables.
D) An independent variable goes from being statistically significant to being insignificant when a new variable is added to the model.
Q. 5A study was done in which the high daily temperature and the number of traffic accidents within the city were recorded. These sample data are shown as follows:
High Temperature Traffic Accidents
91 7
56 4
75 9
68 11
50 3
39 5
98 8
Given this data the sample correlation is:
A) -0.57
B) 0.64
C) 1.54
D) 0.57
Q. 6The frequency distribution of most processes' statistics will begin to resemble the shape of the normal distribution as the values are collected and grouped into classes.
Indicate whether the statement is true or false
Q. 7Both p-charts and c-charts are designed for use when the data we are working with are referred to as attribute data.
Indicate whether the statement is true or false
Q. 8In a multiple regression model, which of the following is true?
A) The coefficient of determination will be equal to the square of the highest correlation in the correlation matrix.
B) Adding variables that have a low correlation with the dependent variable will cause the R-square value to decline.
C) The sum of the residuals computed for the least squares regression equation will be zero.
D) The adjusted R-square might be higher or lower than the value of the R-square.
Quick Reply
