STA3215 Inferential Statistics and Analytics Course Guide

For additional tutorial content by statistics topic, please visit the Brainfuse tutoring platform and select SkillSurfer, as pictured on the left. Resources include:

-Statistics flashcards

-Data collection

-Descriptive statistics

-Displaying data in graphs and charts

-Probability

-Data distributions

-Analyzing data

Access Statistics tutorials in Skillsurfer这里.

eBooks

视频

Statistics for Data Science and Business Analysis - video tutorial

Missing Data Problems and Prospects

权力分析传统与现代的假设Tests

Regression Models for Limited Range Dependent Variables

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For questions about Library resources for Inferential Statistics, chat with a librarian!

我的一位教练推荐了Statdisk。它是教科书附带的软件，它基本上是生活变化。当我听到他们采取推理统计数据时，我已经向这么多学生推荐给了这么多人。

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I don't know if I would have survived my Inferential Statistics class without the Live Help tutors. I'm not really a math guy, but they helped me break it all down until I got it.

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两个词：现场讲座。我的教练很棒，这是提出问题的最佳地点，因为她确切地知道我正在努力的任务。

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Sometimes I felt like I needed to see more examples or have things explained to me in different ways. I had luck with the tutorials in SkillSurfer,and I wish I had known about it from the beginning.

Classifying Data

Levels of Measure

中心措施

Measures of Variation

Normal Distributions

• A bell curve distribution whose shape is determined by a mean and a standard deviation

• Standard Normal Deviations and-分数s

  • When the mean is 0 and the standard deviation is 1 it is called astandardnormal distribution.Measurements on this scale are identified by the variable

• Find a-分数

  • Find a z-score from a probability with =NORM.S.INV(probability)

    • < >: z-scores are not percentages, do not change the decimal place when computing a z-score.

      区域和概率

      • Find a probability from a z-score with =NORM.S.DIST(z, TRUE)

Parameters and Statistics

A parameter is a measurement (usually a proportion, a mean, or a standard deviation) of anentire population. Usually these values are either impossible or unrealistic to find.

A statistic is a measurement used toestimate a parameterthat is based on a sample taken from a population.

Confidence Intervals Overview

• A confidence interval is a range of values used to estimate a population parameter.They are made by using a point estimate obtained from a sample and then calculating a margin of error about that point estimate.

• The point estimate is a single value used to estimate a population parameter.Each parameter type has its own best point estimate statistic.

• Margins of error are computed differently depending on the population parameter being estimated.

• A confidence level () is the probability that the results of our construction of the confidence interval will contain the population parameter.This Wikipedia articlehas a good summary of interpretations with some common misinterpretations.

公式建立信心intervals and minimum sample size can be found in the attachments in the links below:

Either a goodness of fit test or a test of independence will always a right-tailed test and use astatistic for the test statistic and critical value.

测试统计：

• is the observed value

• is the expected value, this must be computed independently and the type of computation varies by the type of test

本福德的法律：

领先的数字	1	2	3	4	5	6	7	8	9
Percentage	30.1	17.6	12.5	9.7	7.9	6.7	5.8	5.1	4.6

Tests of Independence:

Critical Value:The critical value is the same set-up for either type of test

• CHISQ.RT.INV(alpha, d.o.f.)

  • 本福德的法律：d.o.f.

    • The d.o.f. for Benford’s Law is always 8

  • 独立性的测试：

    d.o.f

打开位于此框底部的附件，用于以下主题：

Steps of Hypothesis Test

Null Hypothesis

Alternative Hypothesis

Critical Value Excel Formulas

P-Value Excel Formulas

Test Statistic and Critical Value Types

Test Statistic Formulas

Dependent Samples

Linear Correlation

A correlation exists if the values of one variable are somehow associated with the values of the other variable

Correlation does not imply causation

Correlation Coefficient

We use the variable测量线性相关的强度。

In Excel use=CORREL(x data, y data)

Wheneverwe conclude that there is no significant linear correlation.

Critical value is determined by the significance level and the sample size. See Appendix A in textbook for table of critical values of correlation coefficients.

Ifwe say there is a positive linear correlation.

If我们说存在负线性相关性。

确定系数

The proportion of variance in the dependent variable that is predictable from the independent variable.

The coefficient of determination is also simply the square of the correlation

coefficient.

Regression Equation

- 独立变量

– best predicted value

– y – intercept

=INTERCEPT(y data, x data)

– slope

=SLOPE(y data, x data)

Outliers and Influential Points

An outlier is a point that is far away from other data points

An influential point is a point that strongly affects the regression line