A couple of observations: the sample size is fairly small given the initial results. Using the SAS Power and Sample Size Tool yielded these narratives:
"For a two-sample pooled t test of a normal mean difference with a two-sided significance level of 0.05, assuming a common standard deviation of 51, a sample size of 110 per group is required to obtain a power of at least 0.95 to detect a difference between the means 143 and 118. The actual power is 0.951.

For a two-sample pooled t test of a normal mean difference with a two-sided significance level of 0.05, assuming a common standard deviation of 39, a sample size of 53 per group is required to obtain a power of at least 0.9 to detect a difference between the means 143 and 118. The actual power is 0.905."

This could get expensive for dad.

What looks interesting to me in the graphs is the possibility that the variances might be different between the two brands.