For Exercises 13.1 and 13.2, see page 651; and for 13.3 and 13.4, see pages 655-656.
13.5 Lag 0.
The ACF shown in Figure 13.10 (page 654) starts with lag 1. However, some software will report and plot the autocorrelation for lag 0. Regardless of the series involved, what is the value of the lag 0 autocorrelation?
13.5
1.
13.6 Annual inflation rate.
Here are the annual inflation rates for the United States for the years 2000 through 2013:
| Year | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 |
| Percent (%) | 3.4 | 2.8 | 1.6 | 2.3 | 2.7 | 3.4 | 3.2 |
| Year | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 |
| Percent (%) | 2.8 | 3.8 | −0.4 | 1.6 | 3.2 | 2.1 | 1.5 |
13.7 Runs test output.
Here is the runs test output for a time series labeled X:
Runs test for X
Runs above and below K = 200.742
The observed number of runs = 53
The expected number of runs = 44.9091
46 observations above K, 42 below
P-value = ???
13.7
(a) . (b) .
13.8 Randomness versus distribution.
In this section, we defined a Normal random process as being a process that generates independent observations that are well described by the Normal distribution. Consider daily data on the average waiting time (minutes) for patients at a health clinic over the course of 50 consecutive workdays.
clinic