Social Statistics: Chart

Range Standard deviation Variance Using Excel to calculate them

Review

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Label everything One graph communicate one idea Keep things balanced Simple is best

A picture is worth a thousand words

Chart

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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

Frequency distribution

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Exercise

50 scores Set class intervals Create a histogram using your hand Using Excel to do that

Score47244417635383536101114143030323334323131151617

16151918162525262627292928292720212121242423202120

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A histogram

0-4 5-9 14-10 15-19 20-24 25-29 30-34 35-39 40-44 45-490

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Histogram Chart

class interval

Fre

qu

ency

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First, define your bins The starting point of a bin Data analysis Toolpak histogram

Excel for Histogram

24 29 19 34 14 39 9 44 4 49 More0

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0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

120.00%

Histogram

Frequency

Cumulative %

Bin

Fre

qu

ency

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Skewness Measure of the lack of symmetry of a distribution

mean>median>mode positively skewed mean<median<mode negatively skewed

Skewness

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Skewness

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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

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Skewness

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

Kurtosis

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Variability (S-p97-Fig 4.14)

Variability

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Excel: SKEW() and KURT() 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.

Frequency distribution

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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.tc3.edu/instruct/sbrown/stat/shape.htm)

Exercise

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# of Children Males Females

0 94 921 52 722 71 1273 47 914 30 38

5 or more 33 27Total(N) 327 447