Multivariate Flashcards 1

What type of data consists only of names, labels, or categories, and cannot be ranked or ordered?

Nominal (qualitative data)

What type of data can be arranged in an order (e.g., low to high) but does not have a quantitatively fixed space between each item?

Ordinal (qualitative data that can be ranked)

What type of data has meaningful intervals but not meaningful ratios, and has an arbitrary zero point?

Interval (quantitative data)

What is the definition of the Mode?

The most common value in a data set.

Which measure(s) of central tendency/summary should you use for Nominal data?

Mode only

Which measure(s) of central tendency/summary should you use for Ordinal data?

Mode, Median, & Range

Which measure(s) of central tendency/summary should you use for Interval-ratio data?

Mean, Median, Mode, Range, & Standard Deviation

Describe the shape and key property of a Normal distribution.

Symmetrical/even distribution; with enough added data, even non-normal distributions (e.g., bi-modal) can become normal; Central Limit Theorem: the sample looks like the population as more data is collected

What is a Z-score and why is it crucial?

A formula that changes a raw score to a standardized/normalized score; identifies one's position within a distribution; crucial for comparing variables with different units (e.g., income $, education years, # of children)

What is a Sampling Distribution?

A theoretical distribution of a statistic (mean, proportion, etc.) for all possible samples of a given size (N). It does not exist empirically.

According to probability theory, what is the relationship between the mean of the sampling distribution (Mx̅) and the true population mean (Mx)?

They are equal: Mx̅ = Mx

What is a Point Estimate?

A sample statistic (e.g., sample mean, proportion) used to estimate the exact value of a population parameter.

What is a Confidence Interval?

A range (rather than a single point) built around a sample statistic, within which the population parameter is likely to fall.

How does the width of a confidence interval relate to confidence level?

Confidence in a range goes up the wider it is, because it can account for more possible values.

What is the default confidence interval used in this class, and what is its general formula?

95% confidence interval; Formula: (x̅ - margin of error) to (x̅ + margin of error) or (X̅ - E) < µ < (X̅ + E)

What is the purpose of a One sample t-test?

To compare a random sample from a subpopulation against a large population.

In hypothesis testing, when do you reject the null value?

If P < 0.05 (less than 0.05 means it is unlikely the observed difference is due to random chance)

What does ANOVA stand for and what is its purpose?

Analysis of Variance; used to compare differences across more than two groups