Exam 1

  1. Metainformation

    Tag Value
    fileDescriptive-statistics_eur-descriptive-126-en_eur-descriptive-126-en
    nameeur-descriptive-126-en
    sectionDescriptive statistics/Summary Statistics/Measures of Spread/Standard Deviation
    typenum
    solution1.304
    tolerance0.01
    TypeCalculation
    ProgramCalculator
    LanguageEnglish
    LevelStatistical Literacy

    Question

    Below you find the scores of six students on the course 1.1 exam (social psychology) and the course 1.3 exam (statistics). For both exam scores calculate the standard deviation.

    Students Exam Course 1.1 Exam Course 1.3
    1 7.5 6.8
    2 6.2 5.4
    3 5.2 7.6
    4 8.2 7.6
    5 9.2 8.4
    6 6.9 4.7

    Calculate standard deviation of the exam scores for course 1.3


    Solution

    Students Exam Course 1.3 Squared Deviation 1.3
    1 6.8 (6.8 ‐ 6.75)(6.8 ‐ 6.75)
    2 5.4 (5.4 ‐ 6.75)(5.4 ‐ 6.75)
    3 7.6 (7.6 ‐ 6.75)(7.6 ‐ 6.75)
    4 7.6 (7.6 ‐ 6.75)(7.6 ‐ 6.75)
    5 8.4 (8.4 ‐ 6.75)(8.4 ‐ 6.75)
    6 4.7 (4.7 ‐ 6.75)(4.7 ‐ 6.75)
    Sum 40.5 10.195
    Mean 6.75 1.699

    The mean is calculated by summing the scores on the exam and dividing this sum by the number of participants:

    Mean Exam 1.3 = 40.506=6.75\frac{40.50}{6} = 6.75

    A deviation score is calculated by subtracting the individual score from the mean. The variance is calculated by squaring these deviation scores, summing those and divide this sum by N.

    Variance Exam 1.3 = 10.1956=1.699\frac{10.195}{6} = 1.699

    The standard deviation is calculated by taking the square root of the variance.

    Standard deviation Exam 1.1 = 1.699=1.304\sqrt{1.699} = 1.304