Hypothesis Testing

Executive Summary

Hypothesis testing is the formal statistical framework used to test claims about population parameters. By comparing sample statistics against null expectations, researchers determine if observed differences are statistically significant or just random noise.

Key Takeaways
  • significance check: Hypothesis testing evaluates if sample evidence deviates sufficiently from a null hypothesis to reject it.
  • test statistics: Z-score or T-score measures the number of standard errors separating the sample mean from the null mean.
  • p-value criterion: The p-value measures the probability of observing our results if the null hypothesis is true. Reject when p < alpha.
Formula
z = (x̄ - μ₀) / (s / √n)

One-Sample Hypothesis Testing

Variable Glossary
SymbolMeaning & Description
z / tStandardized test statistic
x̄Sample Mean
μ₀Null Hypothesized Mean
SEStandard Error = s / √n
Step-by-Step Worked Example
1. Mapped Variables
Sample Mean (x̄)
x̄105
Null Mean (μ₀)
μ₀100
Standard Deviation (s)
s15
Sample Size (n)
n30
2. Equation Substitution
Equation with standard inputs
z = (105 - 100) / (15 / √30)
3. Calculation Steps
Step 1: Calculate Standard Error (SE)

SE = s / √n = 15 / √30 = 2.7386

Step 2: Solve test statistic

z = (x̄ - μ₀) / SE = (105 - 100) ÷ 2.7386 = 1.8257

Step 3: Determine p-value outcome

Test statistic = 0.06789. p-value = 1.8257

Final Resolved P-Value0.06789
Live Simulation

Hypothesis Testing Calculator Sandbox

Tweak variables below to see the formula calculate instantly.

105
100
15
30
P-Value
0.06789
Test Statistic
1.8257
Standard Error (SE)
2.7386
H₀ Null Mean
100
How This Result Is Calculated (Step-by-Step)
Step 1: Calculate Standard Error (SE)

SE = s / √n = 15 / √30 = 2.7386

Step 2: Solve test statistic

z = (x̄ - μ₀) / SE = (105 - 100) ÷ 2.7386 = 1.8257

Step 3: Determine p-value outcome

Test statistic = 0.06789. p-value = 1.8257

Common Mistakes to Avoid

Accepting the Null Hypothesis: If a p-value is greater than alpha (e.g. 0.05), we do not "prove" the null hypothesis is true. We simply "fail to reject" it due to insufficient evidence.

Frequently Asked Questions
Interactive Tool

Hypothesis Testing Calculator

Perform one-sample z/t hypothesis testing and compute exact p-values.

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