An apparent 'even-odd' cycle distribution in Mt. Wilson 'numbers of spots' data

Mt. Wilson 'numbers of spots' data (Howard et al., 1984) appear to be distributed according to 'even-odd' cycle numbering. Linear fits of annual 'numbers of spots' versus annual sunspot number for even- and odd-numbered cycles have slopes which are statistically different at the 5 percent level of significance. The existence of an 'even-odd' split in Mt. Wilson 'numbers of spots' data may be due either to a real difference in even- and odd-numbered cycles on the sun or to a difference in weather at Mt. Wilson during even- and odd-numbered cycles, or both. For cycle 22, an even-numbered cycle, the peak 'numbers of spots' is estimated to be near 2600.