The scatter plot shows the relationship between the number of hours spent practicing piano per week and the number of pieces of music the student can play:
A scatter plot is shown. The x-axis is labeled hours spent practicing and the y-axis is labeled number of pieces student can play. Data points are located at 1 and 1, 1 and 5, 2 and 10, 2 and 15, 3 and 15, 3 and 25, 4 and 40, 5 and 40, 5 and 50, 6 and 55, 6 and 70, 8 and 90, 3 and 70. A circle labeled T includes all points except for 3 and 70. Point 3 and 70 is circled and labeled as R.
Part A: What is the group of points labeled T called? What is the point labeled R called? Give a possible reason for the presence of point R. (3 points)
Part B: Describe the association between the number of hours practiced each week and the number of pieces a piano student can play. (2 points)
Part A: The group of points labeled T is called a cluster or a trend. Point R is called an outlier. Point R may be present due to a variety of factors, such as the student being particularly talented or dedicated to practicing, or potentially making an error in recording the data.
Part B: The association between the number of hours practiced each week and the number of pieces a piano student can play appears to be positive. As the number of hours practiced per week increases, the number of pieces the student can play also tends to increase. This suggests that there is a relationship between practice time and skill level in playing the piano.