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April 1980

Is There Seasonal Variation in the Birth of Left-handed Schoolgirls?-Reply

Author Affiliations

Children's Hospital Medical Center 300 Longwood Ave Boston, MA 02115

Arch Neurol. 1980;37(4):254-255. doi:10.1001/archneur.1980.00500530092028

In Reply.—  We are delighted that our report has prompted others to consider this hypothesis.Edwards' method is designed to appreciate cyclical patterns. As such, just one high value for one of 12 months would tend not to be identified as the peak of a sinusoidal pattern. Indeed, in our data the rate of left-handedness in girls was lower in November than it was in October and December. Thus, the claim that our observation represents random phenomena because we looked at 24 occasions (two sexes over 12 months) is inappropriate.The word "separate" in our report was not intended to convey independence. If we had wanted to imply independence, we would have used that word specifically. Evidence that measures of handedness defined by separate tasks are indeed correlated has already been published.1The use of analysis of variance by Hicks and Dusek is inappropriate to the study of cyclical patterns.2

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