9; 9.5; 9.5; 10; 10; 10; 10; 10.5; 10.5; 10.5; 10.5; 11; 11; 11; 11; 11; 11; 11.5; 11.5; 11.5 The average age is 10.53 years, rounded to 2 places. The variance may be calculated by a table. Then the standard deviation is calculated by taking the square root of the variance. We will explain the parts of the table after calculating s. The sample variance, is equal to the sum of the last column (9.7375) divided s2, by the total number of data values minus one (20 - 1): = 9.7375/(20 1) = 0.5125 s2 − The sample standard deviation is equal to the square root of the sample s variance: Rounded to two decimal places, = 0.72 . s
9; 9.5; 9.5; 10; 10; 10; 10; 10.5; 10.5; 10.5; 10.5; 11; 11; 11; 11; 11; 11; 11.5; 11.5; 11.5 The average age is 10.53 years, rounded to 2 places. The variance may be calculated by a table. Then the standard deviation is calculated by taking the square root of the variance. We will explain the parts of the table after calculating s. The sample variance, s2, is equal to the sum of the last column (9.7375) divided by the total number of data values minus one (20 - 1): s2 = 9.7375/(20 − 1) = 0.5125 The sample standard deviation s is equal to the square root of the sample variance: . Rounded to two decimal places, s = 0.72
ch_2_10_calculatingstandarddeviation.docx