Question

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; −3; 1; −1; 6; 5; −2

i. What is the standard deviation for this sample? (Round your answer to two decimal places.)

ii. Find the change score that is 2.2 standard deviations below the mean. (Round your answer to one decimal place.)

Answer 1

a)

sd = 3.542

b)

mean - 2.2 * sd

= 2 - 2.2*3.542

= -5.7924

= -5.8

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