4. Statistical Quality Control in Mix Design

Try these first

1. 1.

   Define standard deviation in your own words.

   Hint

   Think about how spread out the numbers are.

2. 2.

   What does a higher coefficient of variation indicate?

   Hint

   It’s a ratio comparing standard deviation to mean.

3. 3.

   What does standard deviation measure?

   • Consistency of results
   • Average value
   • Deviation from the mean

   Hint

   Think about how closely your results cluster around the average.

4. 4.

   True or False: A higher coefficient of variation indicates lower variability.

   • True
   • False

   Hint

   Recall what CV represents.

5. 5.

   Given the following data: 15, 22, 19, 21, and 25 MPa, calculate the standard deviation and interpret the results in the context of concrete quality.

   Hint

   Remember to calculate the mean first and then use the standard deviation formula.

6. 6.

   If a control chart is showing consistent readings above the UCL for several consecutive days, what actions should be taken, and why?

   Hint

   Focus on the consequences of unregulated strength deviations.