1. The zone tests (Four Western Electric (WE) rules) are used in statistical control charts (SPC) to identify patterns of:

   1. Invalid variation.

   2. Residual variation.

   3. Common variation (noise).

   4. Special variation (signal).

2. Random variation around the centerline which do NOT satisfy any of the four WE rules are indications for:

   1. Noise, meaning no specific action is necessary.

   2. Noise, meaning specific actions are necessary to get the project back on track.

   3. Signal, meaning specific action is necessary.

   4. Signals, meaning specific actions are not necessary.

3. Which of the following statistical moments are used in a SPC chart to estimate the value of statistical dispersion:

   1. Mode.

   2. Range.

   3. Mean.

   4. Kurtosis.

4. A complete SPC chart checks for:

   1. Differences between data points.

   2. Variation and Location.

   3. Mean and Median.

   4. Range.

5. If the tolerance of a project requirement has the Lower Natural Process Limit = 50 days and the Upper Natural Process Limit = 90 days, the target of the spec is usually

   1. 90 days.

   2. 70 days.

   3. 140 days.

   4. 50 days.