Social Statistics Chart Review Range Standard deviation Variance

Social Statistics: Chart

Review ¥ Range ¥ Standard deviation ¥ Variance ¥ Using 2 Excel to calculate them

Chart ¥ Label everything ¥ One graph communicate one idea ¥ Keep things balanced ¥ Simple is best ¥A 3 picture is worth a thousand words

Frequency distribution ¥ Frequency distribution is a method to represent the frequency of certain scores. ¥ When you have a data set, such as a testing scores, ¥ Class intervals Number of intervals: 5, 10, 20 ¥ Value of interval=range/number of intervals ¥ 4

Exercise ¥ 50 scores Score 47 2 44 41 7 6 35 38 35 36 10 11 14 14 30 30 32 33 34 32 31 31 15 16 17 Set class intervals ¥ Create a histogram using your hand ¥ Using Excel to do that ¥ 5 16 15 19 18 16 25 25 26 26 27 29 29 28 29 27 20 21 21 21 24 24 23 20 21 20

A histogram Histogram Chart 12 Frequency 10 8 6 4 2 0 0 -4 5 -9 14 -10 15 -19 20 -24 25 -29 class interval 6 30 -34 35 -39 40 -44 45 -49

Excel for Histogram ¥ First, define your bins The starting point of a bin ¥ Data analysis Toolpak histogram ¥ Frequency Histogram 12 120. 00% 10 100. 00% 8 80. 00% 6 60. 00% 4 40. 00% 2 20. 00% 0 0. 00% 24 7 29 19 34 14 39 Bin 9 44 4 49 More Frequency Cumulative %

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Skewness ¥ Measure of the lack of symmetry of a distribution ¥ mean>median>mode positively skewed ¥ mean<median<mode negatively skewed 9

Skewness 10

Skewness Median for frequency distributions: N=total number of respondent (n=1414), If n=even number, n/2=707, if n= odd, (n+1)/2. So in fy column, 707 fits to 717 which has 3 siblings, so median=3. Or in c%, 50% fits to 63. 2%, which is 3 siblings 11

Skewness 12

Kurtosis ¥ 13 Kurtosis: the degree of peakedness or flatness of a probability distribution

Variability ¥ Variability 14 (S-p 97 -Fig 4. 14)

Frequency distribution ¥ Excel: SKEW() and KURT() ¥ ¥ 15 Skewness characterizes the degree of asymmetry of a distribution around its mean. Positive skewness indicates a distribution with an asymmetric tail extending toward more positive values. Negative skewness indicates a distribution with an asymmetric tail extending toward more negative values. Kurtosis characterizes the relative peakedness or flatness of a distribution compared with the normal distribution. Positive kurtosis indicates a relatively peaked distribution. Negative kurtosis indicates a relatively flat distribution.

Exercise ¥ 16 From General Social Survey 2010, we reported the number of children showed in the subsample of male and female respondents. ¥ Create a histogram using your hand ¥ Using Excel to do that ¥ Mean, mode and median ¥ Skewness (for more details on how to calcualte skewness, http: //www. tc 3. edu/instru ct/sbrown/stat/shape. htm) # of Children Males Females 0 94 92 1 52 72 2 71 127 3 47 91 4 30 38 5 or more 33 27 Total(N) 327 447