Jillian is using integer tiles to add 7 + (negative 2). She uses the steps below. Step 1 7 positive tiles. Step 2 7 positive tiles and 2 negative tiles. Step 3 7 positive tiles and 2 negative tiles. 2 positive and 2 negative tiles are circled. Step 4 7 + (negative 2) = 2 Jillian has made an error. In which step does it occur? Step 1 Step 2 Step 3 Step 4

3.17 scores on stats final. below are final exam scores of 20 introductory statistics students. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 57, 66, 69, 71, 72, 73, 74, 77, 78, 78, 79, 79, 81, 81, 82, 83, 83, 88, 89, 94 (a) the mean score is 77.7 points. with a standard deviation of 8.44 points. use this information to determine if the scores approximately follow the 68-95-99.7% rule. (b) do these data appear to follow a normal distribution? explain your reasoning using the graphs provided below.