In an extensive study involving thousands of British children, Arden and Plomin (2006) found

1. In an extensive study involving thousands of British children, Arden and Plomin (2006) found significantly higher variance in the intelligence scores for males than for females. Following are hypothetical data, similar to the results obtained in the study. Note that the scores are not regular IQ scores but have been standardized so that the entire sample has a mean of M=10 and a standard deviation of s=2
a. Calculate the mean and the standard deviation for the sample of n=8 females and for the sample of n=8 males.
b. Based on the means and the standard deviations, describe the differences in intelligence scores for males and females.

Female: 9, 11, 10, 13, 8, 9, 11, 9
Male: 8, 10, 11, 12, 6, 10, 14, 9

2. A sample of n = 6 scores has a mean of M = 5. If one new person with a score of X = 8 is added to the sample, what is the value for the new mean?