Question

2.5. Here are data on the number of people bitten by alligators in Florida over a 36-year period. Make two graphs of these data to illustrate why you should always make a time plot for data collected over time a) Make a histogram of the counts of people bitten by alligators. The distribution has an irregular shape What is the midpoint of the yearly counts of people bitten? b) Make a time plot. There is a great variation from year to year, but also an increasing trend. How many of the 22 years from 1986 to 2007 had more people bitten by alligators than your midpoint from (a)? What can you conclude from this data? YearNumber Year N NumberY bitten 10 Year Number Year Numb bitten bitten bitten 16 23 25 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 20 19 20 12 23 18

Answer 1

(a)

Following is the frequency distribution of "Number bitten":

Number bitten 1-5 5-10 10-15 15-20 20-25 25-30 Frequency 7

Following is the histogram:

There are 36 data values so midpoint will be average of 18th and 19th data value. Since 18th and 19th data values are 13 and 13 respectively so midpoint is 13.

(b)

Following is the time series plot:

Out of 22 years, 15 had more people bitten by alligators than your midpoint.