Z Score Calculator

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Z Score  Calculator Z Score Calculator

2️⃣ Z-Score to Probability
3️⃣ Probability Between Two Z-Scores

Description

📊 Z-Score Calculator – Measure Standard Deviations Easily

The Z-Score Calculator is a powerful statistical tool that helps students, teachers, researchers, and professionals understand how far a data point is from the mean of a dataset. Whether for hypothesis testing, grading systems, or analyzing distributions, this calculator makes Z-scores simple and easy to interpret.


📘 What It Calculates:

Z-Score from Raw Score (e.g., given x, μ, σ → find z)

Raw Score from Z-Score (e.g., given z, μ, σ → find x)

Sample or Population Data – supports both types

Step-by-Step Calculations for clarity

Probability Insights using the standard normal distribution curve


💡 Features:

  • Easy input for raw scores, mean, and standard deviation

  • Automatic step-by-step solution with explanations

  • Works with normal distribution for probability analysis

  • Helps detect outliers, unusual values, or relative positions

  • Great for academic learning and professional analysis


👤 Who Should Use This:

📌 Students & Teachers – for statistics, probability, and exam prep
📌 Researchers – to assess normality and detect outliers
📌 Psychologists & Social Scientists – to interpret standardized test scores
📌 Finance Analysts – to evaluate investment performance relative to benchmarks


🧮 Formula Used:

Z-Score Formula:

z=x−μσz = \frac{{x - \mu}}{{\sigma}}z=σx−μ​

Where:

  • z = Z-score

  • x = raw data value

  • μ = mean

  • σ = standard deviation

Inverse Formula (to find x):

x=z⋅σ+μx = z \cdot \sigma + \mux=z⋅σ+μ


📌 Example:

  • Raw score: x = 85

  • Mean: μ = 75

  • Standard deviation: σ = 5

z=85−755=2z = \frac{{85 - 75}}{5} = 2z=585−75​=2

👉 Interpretation: The score is 2 standard deviations above the mean.


✅ Pro Tip:

Don’t just calculate—interpret the Z-score. Knowing whether a value is typical, unusual, or an outlier provides deeper statistical insight.


🔗 Related Tools You May Find Helpful:

Standard Deviation Calculator – Find variability in data
📈 Root Calculator – Probability & curve analysis
🧮Ratio Calculator – Understand central tendency

z= σ x−μ ​ = 7.5 90−75 ​ = 7.5 15 ​ =2 ✅ Answer: Z = 2 (the score is 2 standard deviations above the mean).

z= 3 64−70 ​ = 3 −6 ​ =−2 ✅ Answer: Z = -2 (the man is 2 standard deviations below the mean).

x=z⋅σ+μ=1.5⋅50+500=75+500=575 ✅ Answer: Raw score = 575