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