One hundred teachers attended a seminar on mathematical problem solving. The attitudes of representative sample of 12 of the teachers were measured before and after the seminar. A positive number for change in attitude indicates that a teacher's attitude toward math became more positive. The twelve change scores are as follows.

4; 8; 1; 2; 0; 5; 2; 1; 1; 6; 5; 3

• Part (a)
• What is the mean change score? (Round your answer to two decimal places.)
• Part (b)
• What is the standard deviation for this sample? (Round your answer to two decimal places.)
• Part (c)
• What is the median change score? (Round your answer to one decimal place.)
• Part (d)
• Find the change score that is 2.2 standard deviations below the mean. (Round your answer to one decimal place.)