A student's first three math test scores are 80, 85, and 90. A fourth test score of 70 is added to the data set. Which of the following statements correctly compares the mean of the first three scores to the mean of all four scores?
The mean of the first three scores is greater than the mean of all four scores.
The mean of the first three scores is less than the mean of all four scores.
The means of both data sets are equal.
There is not enough information to compare the means.
