Standard Deviation/Standard Score Correspondence

Standard Deviation/Standard/Scaled Score Correspondence Standard Deviation (SD) Standard Score Scaled Score 2 SD above mean 130 or above 16 or above 1 SD above mean Between 115 and 130 Between 13 and 16 Within 1 SD of mean Between 85 and 115 Between 7 and 13 1 SD below mean Between 70 and 85 Between 4 and 7 1.5 SD below mean 77.5 5.5 2 SD below mean 70 or below 4 or below

From the WJ-III ACH Test Standard Descriptor Percentile 95% Standard Score Rank Confidence Deviation Interval Letter-Word 78 Low 7 72 – 83 - 1.5 SD Identification Reading Fluency 82 Low 12 79 – 85 - 1 SD Average Passage 90 Average 26 80 – 101 * Comprehension Calculation 88 Low 21 78 – 97 * Average Math Fluency 83 Low 13 78 – 87 - 1 SD Average Applied Problems 91 Average 28 86 – 96 * Spelling 77 Low 7 70 – 85 - 1.5 SD Writing Samples 92 Average 31 75 – 110 * Writing Fluency 86 Low 18 79 – 94 * Average * Not significant – within 1 standard deviation of the mean

From the TOWRE Score Percentile Description Standard Deviation Sight Word Efficiency 83 13 Below Avg. - 1 SD Phonemic Decoding 76 6 Poor - 1.5 SD Efficiency Total Word Reading 75 5 Poor - 1.5 SD Efficiency