An experiment was conducted to study the effect of eating walnuts on the quality of sperm.2 The subjects were healthy men 21-35 years old. The treatment group received 75 gm of whole-shelled walnuts a day for 12 weeks. This was a single blind trial where the assessors of sperm quality were not told the group membership. Measurements were made at the start of study and again at the 12-th week visit. The statistical analysis is based on the change in vitality, final - initial, where vitality is the percent of sperm alive. The summary statistics are

Is the mean change for the walnut eating group significantly higher than for the control group? Answer by calculating the P-value.

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Vitality (% alive) Walnut Group Control Group Number Mean Standard deviation10. 52 5.5 51 7.4