Consider the data on the number of earthquakes of magnitude 7.0 or greater by year in Exercise 6-87.

(a) Construct a U chart for this data with a sample size of n = 1.

(b) Do the data appear to be generated by an in-control process? Explain.

Exercise 6-87

Table 6E.3 shows the number of earthquakes per year of magnitude 7.0 and higher since 1900 (source: Earthquake Data Base System of the U.S. Geological Survey, National Earthquake Information Center, Golden, Colorado). Construct and interpret either a digidot plot or a separate stemand-leaf and time series plot of these data.

Table 6E.3

Transcribed Image Text:

1900 13 1928 22 1956 15 1984 8. 1957 1901 14 1929 19 34 1985 15 6. 1902 1930 13 1958 8. 10 1986 1903 10 1931 26 1959 15 1987 11 1960 1904 1932 13 22 1988 16 1905 1933 1961 1989 26 14 18 1906 1934 1990 32 22 1962 15 18 1907 27 1935 24 1963 20 1991 16 1992 1908 18 1936 21 1964 15 13 1909 32 1937 22 1965 22 1993 12 1938 1966 1910 36 26 19 1994 13 1939 1995 1911 24 21 1967 16 20 1912 22 23 30 15 1940 1968 1996 1913 23 1941 24 1969 27 1997 16 1942 1914 22 27 1970 29 1998 12 1943 41 23 1999 1915 18 1971 1972 1973 18 25 1916 2000 1944 1945 1946 1947 1948 1949 31 20 15 16 1917 21 27 2001 2002 2003 16 35 1974 1975 1976 1977 1978 1979 1980 1918 21 21 13 21 25 16 1919 14 26 15 28 2004 2005 1920 16 11 11 11 1921 1922 36 14 1950 39 18 2006 2007 2008 1923 23 21 15 1951 1952 1953 18 1924 1925 1926 1927 18 17 19 17 18 12 22 2009 1981 1982 1983 14 15 1954 17 10 1955 19 20 15