The studio notebook
Practical guides from Z Table
6 guides to use with the Z table and area lookup: Positive and negative z tables with four-decimal areas, plus a lookup for left, right and two-tailed areas and the z-score for any area. Free to print.
How to Read a Z Table (Left-Tail Areas, Step by Step)
Learn to read a standard normal z table: find the row and column, get left-tail, right-tail and between-two-values areas, and handle other table layouts.
Z-Score Formula and Worked Examples
Use the z-score formula z = (x − μ) / σ, read what the sign and size mean, convert a z-score to a percentile, and handle sample means with σ/√n.
Sample vs Population Standard Deviation (n vs n − 1)
Know when to divide by n and when to divide by n − 1, with the formulas, a worked data set, the link to variance, and the mistakes that cost points.
Mean, Median and Mode: Definitions, Examples and Which to Use
Find the mean, median and mode of a data set, see how one outlier moves each one, and decide which measure of center to report for your data.
T Table vs Z Table: Which One to Use and How to Read It
Decide between the t table and z table, find degrees of freedom, read one-tailed and two-tailed columns, and see why t values approach z as df grows.
How to Read a Chi-Square Table (df, Critical Values, p-Values)
Find degrees of freedom for goodness-of-fit and independence tests, read right-tail critical values, and compare them with your chi-square statistic.