Statistics for EMCL students
Overview before final exam
- Descriptive statistics
(M&M 1.1 and 1.2,
- More variables: independence, correlation, regression (M&M 2).
- Basics of inferential statistics: sampling distributions,
confidence intervals, tests. Experiment design, ethical
issues, etc. (M&M 3, 5.2, 6).
- Statistical procedures (tests and confidence interval): z-test
and confidence interval (one-sample), t-test (one-sample
and two-sample; confidence interval with t-statistic),
test for proportions, chi-square, ANOVA,
nonparametric tests (esp. Wilcoxon rank sum test).
Can you define in one sentence the following concepts?
- Informed consent (For those using earlier editions of M&M:
check 3.4 in the newest version!).
- Variable: nominal, ordinal, numerical scales.
- Measures of center vs. measures of spread.
- Resistant measure (NB: resistancy is a relative and not an
- Density curve vs. cumulative proportion.
- Sample vs. population. Statistic vs. parameter.
- Bias and variability of a statistic. How to avoid them?
- Confidence level, significance level, p-value,
error margin (in a confidence interval), critical value
(of a distribution for a priori set up significan level).
- Parametric vs. nonparametric statistical procedure.
- Histogram, boxplot, stemplot, normal quantile plot, scatterplot.
- Null hypothesis vs. alternative hypothesis.
- One-side vs. two-sided hypotheses.
- Error of type I vs. error of type II. Connection to p-value.
- Independent samples vs. paired (matched) data samples.
- A robust statistical procedure.
- The 68-95-99.7 rule. The 1.5 X IQR rule.
- The Central Limit Theorem.
- Explanatory variable vs. response variable. Lurking variable.
- Two variables are independent vs. associated.
Positive association vs. negative association.
Association vs. causation.
- Slope vs. intercept.
- Two-way table. Column variable vs. row variable.
Joint distribution, marginal distribution, conditional
distribution. Observed counts vs. expected counts.
- What is the goal of least-squares regression? What are the
possible values of correlation r, and what is their meaning?
- For what purpose do we use... a Normal quantile plot, a
scatterplot, a chi-square test, a matched pairs t-test, etc.?
- When do we use a "contrast" (cf. ANOVA)? Why do we use
Bonferroni in multiple comparisons?
- Under what conditions may you use test ...?
Formulas etc. that you need to know:
- How to compute: mean (a.k.a. average), median, mode,
standard deviation, variance, IQR. Degree of freedom.
- Conversion to standard z-scores.
- Standard error for samples over n elements.
- Use of tables for z, t, chi-square.
- Interpret SPSS output for z, t, chi-square, ANOVA and Wilcoxon.
For all tests: pay attention to the guidelines for
practical use! Be able to decide when is which test to be used
Type of questions in the test:
- Multiple choice.
- Open questions (answer with one sentence).
- Basic calculations by hand + use of table (provided).
- Interpret graphs and SPSS outputs ("write the magic sentence").
Further practice recommended before the final test:
Paper-and-pen assignments that you should be
able to solve during the final exam (by
Confidence interval, statistical significance
You can expect very similar questions in the final test.
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