Data Test 1

Quantitative data

Numerical Values

Quantitative data

Sat scores, tuition cost, number of students

Qualitative data

Categorical values

Qualitative data

Marital status, college type (public/private)

Simple random sampling

Equal chance for all items.

Simple random sampling

Randomly selecting survey participants using Excel.

Systematic Sampling

Every K-th item after a random start. Ex: survey every 40th student

Stratified Sampling

Divide into strata, sample within each. Ensures subgroup representation

Cluster Sampling

Divide into clusters, randomly select clusters. 

Cluster sampling

Based on geographic region

Strata

Any other grouped data thats not region

Time series

Data collected over time (e.g., monthly sales).

Cross sectional

Data collected at one point in time (e.g., student data for a single year)

Histograms

Quantitative, No gaps, frequency counts one continuous variable, numerical data. Values on x axis

Bar chart

Categorical data, values on y axis, has gaps

Skewed left

Mean is less than the median

Skewed right

Median is more than the median

Standard deviation

Measures the spread of data

Skewness of 0

data is symmettric