References about this question: The t Test for Independent Means; The Distribution of Differences between Means; Estimating the Population Variance; Hypothesis Testing with a t Test for Independent Means; Assumptions of the t Test for Independent Means; Effect Size and Power for the t Test for Independent Means

Question: A political scientist obtained recordings of election-night acceptance speeches of seven newly elected representatives to the U.S. Congress. She counted the number of minutes devoted to urban problems in these speeches. Four of these representatives were from rural districts. They devoted 5, 0, 3, and 4 minutes to urban problems. The other three representatives studied, who were from urban districts, devoted 11, 11, and 14 minutes to urban problems. Do these results suggest that the amount of time devoted to urban problems in acceptance speeches of newly elected representatives to the U.S. Congress differ according to whether they come from rural or urban districts? Use the .05 level

What is the mean of the distribution of differences between means?

In the question above, what is t?