How to Find Z-Score on TI-84 Calculator
If you want to know how to find z score on TI 84, this detailed guide shows multiple practical methods. Whether you need a single z value from raw numbers, the z for a percentile, or z-scores for an entire data set, your TI-84 or TI-84 Plus CE can do it fast. The instructions below work for students, teachers, and professionals.
Want to follow along with a real example? Open our hands-on TI-84 calculator online tool to calculate z-scores in real-time.
1: Using the Z-Score Formula
If you have the raw data point, mean, and standard deviation:
- Press the CLEAR button to ensure a clean screen.
- Enter the formula: (x – mean) / standard deviation. For example, if x = 75, μ = 70, and σ = 5, input: (75 – 70) / 5.
- Press ENTER to compute the z-score. In this example, the result is 1.
2. Finding Percentile from Z (using normalcdf)
To get the percentile for a given z, use normalcdf(.
- Press 2nd then VARS to open DISTR.
- Select 2:normalcdf(.
- For left tail use normalcdf(-1E99, z, 0, 1) where -1E99 is negative infinity substitute. For z = 1, enter normalcdf(-1E99, 1, 0, 1).
- Press ENTER.
Result: 0.841344746 (approx).
3. Finding Z from Percentile (using invNorm)
If you know a cumulative probability or percentile and want the corresponding z value, use invNorm(.
- Press 2nd then VARS to open DISTR.
- Select 3:invNorm(.
- Enter 0.95 then ) so the entry reads invNorm(0.95).
- Press ENTER.
Result: 1.644853626 (approx).
3: Calculating Z-Scores for a Dataset
If you have a list of data points and want to compute the z-scores for each:
- Press STAT, then select 1:Edit to enter the data editor.
- Input your data into list L1.
- Press STAT, navigate to CALC, and select 1:1-Var Stats.
- Press 2nd then 1 to choose L1, then press ENTER.
- Note the mean (x̄) and standard deviation (σx) displayed.
- Return to the data editor (STAT > 1:Edit).
- In list L2, input the formula: (L1 – x̄) / σx.
- Press ENTER to compute the z-scores for each data point in L1, which will be displayed in L2.
What is a Z-Score?
A z-score tells you how many standard deviations a data point is from the mean.
Formula:
z = (x – μ) / σ
Where:
- X = your data value
- μ (mu) = the population mean
- σ (sigma) = the population standard deviation
Similar Guides:
