Statistics 101 Flashcards

Questions and Answers

What is a categorical variable?

A variable that can only have a specific set of values

A type of numerical variable with infinite values

Variables that take on values that are numbers

Variables that take on values that are names or labels (correct)

What is a numerical variable?

Variables that take on values that are indicated by numbers.

Define a continuous variable.

A type of numerical value that has an infinite amount of possible values (within a specified range).

Define a discrete variable.

A numerical variable that can only have a specific set of values. Signup and view all the answers

What is a nominal variable?

A categorical variable that does not fall into a specified order. Signup and view all the answers

What is an ordinal variable?

A categorical value that naturally falls into a specified order. Signup and view all the answers

What does skewed mean in data analysis?

The data has a long 'tail' on one side. Signup and view all the answers

What is standard deviation?

A computed measure of how much scores vary around the mean score. Signup and view all the answers

Define clusters in data.

Groups of data that are close together. Signup and view all the answers

What is segmentation in marketing?

Dividing groups of customers with similar characteristics who are likely to exhibit similar purchase behavior. Signup and view all the answers

What are behavioral considerations?

People tend to answer questions in a way they consider to be socially desirable. Signup and view all the answers

Define bias in statistics.

Consistently over or underestimating what is being estimated. Signup and view all the answers

What is the selection process in sampling?

It's the way in which units/people are purposefully selected to be included in a sample. Signup and view all the answers

Define a biased selection process.

When experimenters use an improper selection method which leads to systematic biases. Signup and view all the answers

What is an estimate?

A number calculated from the data, used to estimate an unknown parameter value. Signup and view all the answers

Define inference in statistics.

Using results from a sample statistic value to draw conclusions about an unknown parameter. Signup and view all the answers

What does parameter mean?

A numerical characteristic or feature of a population. Signup and view all the answers

What are interviewer effects?

Aspects of the interviewer's presence that distort participants' true responses. Signup and view all the answers

What is margin of error?

A measure of the accuracy of a public opinion poll. Signup and view all the answers

Define sample size (n).

The number of individuals in a sample. Signup and view all the answers

What is population size (N)?

The number of individuals in a population. Signup and view all the answers

What is nonresponse bias?

Bias introduced to a sample when a large fraction of those sampled fails to respond. Signup and view all the answers

Define a pilot survey.

A small-scale survey carried out before the main one, to iron out any problems. Signup and view all the answers

What is a poll?

A process of collecting data from a sample or subset of the population in order to determine conclusions about the whole population. Signup and view all the answers

Define population in statistics.

A complete collection of participants who might possibly be measured. Signup and view all the answers

What does precision refer to in statistics?

A measure of how variable the estimates are in repeated sampling. Signup and view all the answers

What are question effects?

Variations in wording that can have an effect on responses. Signup and view all the answers

Define random (chance) error.

An error that occurs when the selected sample is an imperfect representation of the overall population. Signup and view all the answers

What is random sampling?

A sampling technique where each subject is chosen entirely by chance. Signup and view all the answers

Define a representative sample.

A sample that accurately reflects the characteristics of the population as a whole. Signup and view all the answers

What is a sample?

A subset of the population. Signup and view all the answers

What is sample design?

The method used to choose the sample from the population. Signup and view all the answers

Define sampling frame.

A list of individuals from whom the sample is drawn. Signup and view all the answers

What is sampling variation?

Variation of a statistic from one sample to the next caused by selecting random subsets of the population. Signup and view all the answers

Define sampling with replacement.

Once an element has been included in the sample, it is returned to the population. Signup and view all the answers

What does sampling without replacement mean?

Once an element has been included in the sample, it is removed from the population and cannot be selected a second time. Signup and view all the answers

What is selection bias?

Population sampled is not exactly the population of interest. Signup and view all the answers

Study Notes

Categorical and Numerical Variables

Categorical variables are identified by names or labels, lacking numerical significance.
Numerical variables represent values through numbers, classified further into continuous and discrete types.

Continuous and Discrete Variables

Continuous variables can take an infinite number of values within a specified range, allowing for fractional values.
Discrete variables have a limited set of specific values, often whole numbers or counts.

Nominal and Ordinal Variables

Nominal variables do not have an inherent order and categorize data without ranking.
Ordinal variables possess a natural order, allowing for meaningful comparisons between categories.

Data Skewness and Measurement

Skewed data features a long "tail" extending either to the right or left, indicating imbalance in data distribution.
Standard deviation indicates the degree of variability or dispersion of scores around the mean score.

Data Clusters and Segmentation

Clusters represent groups of data points that are in proximity to each other, highlighting patterns.
Segmentation involves categorizing customers with shared characteristics, predicting similar purchasing behaviors.

Behavioural Considerations and Bias

Behavioural considerations highlight that individuals may tailor their answers to align with social expectations, introducing potential bias.
Bias refers to a systematic overestimation or underestimation in measurement.

Sampling Processes

The selection process determines how participants are chosen for a sample, influencing the results' reliability.
Biased selection can lead to systematic errors, undermining the study’s validity and representativeness.

Estimates and Inference

Estimates are numerical approximations derived from data, helping infer unknown parameter values.
Inference utilizes sample statistics to draw conclusions about broader population parameters.

Population and Sample Sizes

The population size (N) is the total number of individuals in a defined group, while the sample size (n) refers to the selected subset.
Nonresponse bias occurs when a significant portion of the sampled population does not respond, skewing results.

Surveys and Polls

Pilot surveys are preliminary studies to identify potential issues before conducting the main survey.
Polls gauge public opinion or behaviors by collecting data from a subset, inferring insights about the entire population.

Precision and Errors in Sampling

Precision describes the variability of estimates when samples are repeatedly drawn, indicating reliability.
Random (chance) errors result from the sample being an imperfect reflection of the overall population.

Sampling Techniques

Random sampling ensures each subject is selected purely by chance, aiming for an unbiased representation.
Sampling can be done with or without replacement, affecting the likelihood of reselecting elements in the sample.

Selection Bias and Sampling Variation

Selection bias arises when the sample diverges from the actual population, compromising the study's validity.
Sampling variation accounts for differences in statistical outcomes across different samples due to random selection.

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Description

Test your knowledge with these flashcards on fundamental statistical concepts. From categorical to discrete variables, this quiz covers essential definitions that every statistics student should know. Perfect for reviewing key terms in Statistics 101.