# Measuring “Position” – Percentiles, Quartiles, and Z-Scores

If Bob gets a 50% on his final history exam, that’s pretty bad right?  Well, that depends on what the average exam score was for…

# Measuring “The Spread” – Range, Interquartile Range, Variance, and Standard Deviation

When we analyze a dataset, we often care about two things: 1. Where the “center” value is located. We often measure the “center” using the…

# Measuring “The Center” – Mean, Median, and Mode

Suppose we have the following dataset of 20 students along with their final exam scores in three subjects: In this dataset, the subjects are the…

# Student t-Value Calculator

Degrees of freedom Probability Level t-value (right-tailed): 1.79588 t-value (two-tailed): +/- 2.20099

# Z Score Area Calculator

Population mean (μ) Population standard deviation (σ) Raw score 1 (X1) Raw score 2 (X2) Z-Score of X1: -1.00000 Area to the right of X1:…

# Sample Size Calculator to Estimate Population Proportion

Confidence Level (%) Estimated True Proportion (leave as 0.5 if unsure) Margin of Error (%) Sample size needed: 468 Sample size = [Z2 * P…

# Variables

What Are Variables? A subject is a person, place, or thing we’re interested in studying. A variable is an attribute that describes the subject in…

# Confidence Interval for Population Proportion

Sample size Number of successess 90% Confidence Interval: (0.471, 0.654) 95% Confidence Interval: (0.454, 0.671) 99% Confidence Interval: (0.420, 0.705)

# Confidence Interval Calculator

Sample mean standard deviation Sample size (n) 90% Confidence Interval: (5.896, 28.104) 95% Confidence Interval: (3.770, 30.230) 99% Confidence Interval: (-0.388, 34.388)

# One Sample t-test Calculator

Choose an option: Enter summary data Enter raw data Group 1 Sample mean Standard deviation Sample size (n) Group 1 Enter hypothesized mean value One-tailed…