Assessing Normality When is the data Normal enough?

Use the Rule 1) Plot the data and check for the shape to be……. 2) Determine if ____ % of the data is within 1 standard deviation 3) Determine if 95% of the data is within ___ standard deviations 4) Determine if ____ % of the data is within ____ standard deviations

Normal Probability Plot  X-axis is the data scale  Y-axis is the z-score scale  All data is converted to its z-score and plotted as (data, z-score)  Data should appear linear if it is Normal

Shape from Normal Probability Plot  Symmetric = Linear  Skewed Right = few large values, so large x-values will fall to the right of the line  Skewed left = few small values, so small values will fall to the left of the line

Refrigerator Space The following is a sample of 36 side-by-side refrigerators and their capacity (in cubic feet). Are the data close to Normal? ENTER IN YOUR CALC IN L1

My Calculator Example On the Emulator