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STA220: Practice of Statistics 1

Section L0301: Health & Life Sciences

September 17, 2013

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Announcement

• TA office hours for this course start this week. They will be held in the Statistics Aid Centre: SS 1091. See Coursera for the schedule.

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From last class …

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Your responses:

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Topics this week:

• One variable statistics: five number summary, percentile, mean, trimmed mean, range, interquartile range (IQR), variance, standard deviation, z-score, frequency, relative frequency

• One variable plots and shape: histogram, dot plot, boxplot, pie chart, bar chart, distribution, skew, modes

• Types of variables: categorical, ordinal, quantitative • Two categorical variables: contingency tables (cross-tabulations or

two-way tables) including marginal, joint, and conditional distributions; side-by-side and stacked bar plots (stacked bar plots for conditional distributions are sometimes called segmented bar plots); independent

• Simpson's Paradox • Features of data and statistics: observations, observational units

(cases), variables, missing values, outliers, robust statistics, the empirical rule

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Today and Thursday:

• Muddiest point requests

• Topics not in videos

• A few problems

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Muddy points:

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Muddy points:

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Muddy points:

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A quartile question:

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Muddy points:

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Shape of distribution

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PercentilesWould you rather be in the 99th percentile or the 1st percentile of the class?

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The 99th percentile is the value such that 99% of the data is less than it.

What is another name for:

• The 25th percentile?

• The 50th percentile?

• The 75th percentile?