the distirbution of test scores for a class is approx. symmetric with a mean of 72 and a standard deviation of 6. the z-score for a test score of 63 is? the z-score for a test score of 87 is? the percent of test scores between 66 and 78 is? the test score that has a z-score of z = 2.5: is? 95% of the test scores are between what values? Woudl a test score of 54 be considered \"unusual\" why? Solution the z-score for a test score of 63 is? Z = (x - u)/sigma = (63-72)/6 = -1.5 [ANSWER] ********* the z-score for a test score of 87 is? Z = (x - u)/sigma = (87-72)/6 = 2.5 [ANSWER] ****************** the percent of test scores between 66 and 78 is? As there are 1 standard deviation from the mean, around 68% are between 66 and 78. [ANSWER, 68%] ******************* the test score that has a z-score of z = 2.5: is? x =u + z*s = 72 + (-2.5)*6 = 57 [ANSWER] *************** 95% of the test scores are between what values? These are within 2 standard deviations (2*6 = 12) from the mean, so it is 72 - 12 to 72 + 12 or 60 to 84. [ANSWER] ******************** Woudl a test score of 54 be considered \"unusual\" why? z = (X-u)/sigma = (54-72)/6 = -3 As |z| > 2, then YES, IT IS UNUSUAL. [ANSWER].