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How-To

Quick Start

Build a two-sided 95%/95% tolerance interval for a single column of continuous data.

Goal

Find bounds that we are 95% confident contain at least 95% of the population.

Sample Data

A single column of continuous measurements. Press Copy for Excel, then paste the table into a blank worksheet.

Measurement
9.8
10.2
10.0
9.7
10.4
9.9
10.1
10.3
9.6
10.0

Steps

1. Press Copy for Excel above the table, click cell A1 in a blank worksheet, and press Ctrl+V. The header row lands in row 1 and the 10 data rows in rows 2 through 11.

2. Select the column of data, including its header.

3. On the QXL Stat Tools tab, choose Analysis Tools > Tolerance Interval.

4. Set the options:

   • Confidence Level (%): 95
   • Percent of Population (%): 95
   • Interval Side: Two-Sided

5. Press Finish.

Result

Quantum XL adds a statistics table with the sample size, mean, and standard deviation, the Normal and Nonparametric bounds, the attained confidence of the nonparametric interval, and the Anderson-Darling normality statistic. It also draws a normal probability plot and a line plot comparing the two intervals. See Output for how to read each part.

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More Examples

Ready for more? See this variation:

• GroupBy: A separate interval per group, and what splitting the sample does to the attained confidence