Introduction to Statistics - Lecture Highlights

A set of question-and-answer flashcards summarizing essential vocabulary, concepts, and methods from the introductory statistics lecture notes.

In statistics, what is meant by the term "population"?

The entire group of individuals or items that we want information about.

What is a "sample" in statistical studies?

A subset taken from the population for the purpose of analysis.

Which word describes a numerical value that summarizes a whole population (e.g., μ or σ)?

Parameter.

What do we call a numerical value calculated from a sample (e.g., x̄ or s)?

Statistic.

Which data type deals with measurable quantities such as height or weight?

Quantitative data.

Data that describe attributes like color or brand are classified as what type?

Qualitative (categorical) data.

A countable variable such as the number of desks is classified as what kind of quantitative data?

Discrete data.

Weight, which can take on any value within a range, is an example of which quantitative subtype?

Continuous data.

What sampling method gives every member of the population an equal chance of being chosen?

Simple random sampling.

When the population is divided into homogeneous groups (e.g., freshmen, sophomores) and samples are taken from each, which sampling technique is this?

Stratified sampling.

Selecting entire pre-existing groups at random and using all members from the chosen groups defines which sampling method?

Cluster sampling.

Choosing every k-th individual from an ordered list is known as what sampling technique?

Systematic sampling.

What is the term for a sampling method based on selecting individuals that are easiest to reach?

Convenience sampling—generally considered poor practice.

A distribution with two equal tails and a central peak is described as what shape?

Symmetrical.

What do we call a distribution with a long tail to the right?

Skewed right (positively skewed).

A distribution that stretches out longer on the left side is said to be what?

Skewed left (negatively skewed).

Which term describes an extreme data point that lies far from the rest of the data?

Outlier.

What statistic measures how many standard deviations a value is from the mean?

Z-score.

Which metric quantifies the average spread of data around the mean?

Standard deviation.

The square of the standard deviation is called what?

Variance.

What procedure tests a claim about a population parameter?

Hypothesis test.

A range of plausible values for a population parameter is known as what?

Confidence interval.

Which value represents the probability of observing the sample result, or one more extreme, if the null hypothesis is true?

P-value.

What symbol (α) indicates the threshold probability for deciding whether to reject the null hypothesis?

Significance level.

Which statistic measures the strength and direction of a linear relationship between two variables?

Correlation.

What statistical technique predicts a response variable (y) based on an explanatory variable (x)?

Regression.