Do young children use cell phones? Apparently so, according to a recent study that reported that children under 12 averaged 137 calls per month compared to 231 calls per month for children 13 to 17 years of age. The two sample sizes were 12 for children under 12 and 15 for children 13 to 17 years of age. Further, the standard deviation for children under 12 was 51.7, while the standard deviation for children 13 to 17 of age was 67.6. Assuming that the variances in the populations are equal, is there a difference in the mean cell phone usage between the two groups?