2. Pulp brightness. Consider the following experiment, which was performed at a pulp mill. Plant performance is based on pulp brightness as measured by a reflectance meter. Each of the four shift operators (denoted by A, B, C, and D) made five pulp handsheets from unbleached pulp. Reflectance was read for each of the handsheets using a brightness tester. The data is given in the table below:

Treatment A B C D 59.8 59.8 |60.7 61.0 60.0 60.2 60.7 60.8 60.8 60.4 60.5 60.6 60. 8 59.9 60.9 60.5 59.8 60.0 60.3 60.5