Statistics Flashcards
What are the 3 consecutive steps of statistical research?
- Designing studies
- Describing and analyzing the collected data
- Drawing inference and making decisions and predictions based
on the data
What is a subject?
The entities that we measure in a study.
What is the population?
All subjects of interest.
What is the sample?
The subset of the subjects in the population for whom we actually obtain data.
What are Descriptive vs. Inferential statistics
Descriptive statistics refers to methods for summarizing the data. Data summaries could be graphs and numbers such as averages and percentages.
Inferential statistics refers to methods of making decisions or predictions about a population based on data obtained from a
sample of that population.
What is a point estimate?
A point estimate is a single number that is our ”best guess” for the parameter.
What is an interval estimate?
An interval estimate is an interval of numbers within which the parameter value is believed to fall.
What is the point estimator for a categorical variable?
The sample proportion ˆp is the point estimate of the population proportion p.
What is the point estimator for a quantitative variable?
The sample mean ̄x is the point estimate of the population mean μ.
What is a confidence interval?
A confidence interval (CI) is an interval containing the most likely values for a parameter. The probability that this method
produces an interval that contains the
parameter is called the confidence level. This is a number chosen to be close to 1, commonly 0.95 (often written “95% CI”).
How many SD are included in 95%
+/-1.96
What is alfa?
significance level: 1- confidence level
What id degrees of freedom (df)?
n - 1
