Quiz 9-13
The method of moving averages is used
to smooth a series
A process is said to be out of control if
1)a point falls above the upper or below the lower control lines.2)a run of eight or more points is observed.
The control chart
1)focuses on the time dimension of a system.2)captures the natural variability in the system.
In a simple linear regression problem, r and b1
must have the same sign
The Y intercept (b0) represents the
predicted value of Y when X = 0
Which of the following is not part of the Shewhart-Demibng cycle?
react
The cyclical component of a time series
represents periodic fluctuations which usually occur in two to ten years
When using the chi-square test for differences in two proportions with a contingency table that has r rows and c columns, the degrees of freedom for the test statistic will be
(r - 1)(c - 1)
Which of the following values of the chi-square distribution cannot occur?
-1.96
When testing for the independence in a contingency table with 3 rows and 4 columns, the degrees of freedom for the test statistic would be
6
Six Sigma is a managerial approach resulting in no more than
6 standard deviations from the mean
Which of the following terms describes the up and down movements of a time series that vary both in length and intensity?
Cyclical component.
The chi-square distribution is not a skewed distribution
False
Which of the following terms might be involved when times series data are recorded monthly or quarterly?
Seasonal component
Which of the following terms describes the overall long term tendency of a time series?
Trend
Given a data set with 10 yearly observations, a 3-year moving average will have more observations than a 5-year moving average.
True
Which of the following is not one of Deming's 14 points?
belief in mass inspection
To determine whether a set of observed frequencies differ from their corresponding expected frequencies, we could apply the
chi-square test
Variation due to the inherent variability in a system of operation is called
common or chance causes
The strength of the linear relationship between two numerical variables may be measured by the
correlation coefficient
The slope (b1) represents
the average change in Y per unit change in X
The coefficient of determination tells us
the proportion of total variation that is explained
Assuming a linear relationship between X and Y, if the coefficient of correlation (r) equals -.30
the slope (b1) is negative
The chi-square test can be used
to test for homogeneity of proportions