Once the ground-workers made the concrete you took samples as the concrete was poured into the foundations. These samples were taken to the laboratory and after seven days the results returned were as follows:

Ultimate Strength of Concrete Cubes (N/mm˛)

15, 15, 10, 11, 20, 20, 11, 12, 18, 18, 12, 12, 13, 13, 13, 18, 19, 19, 14, 14, 14, 14, 13, 13, 13, 14, 14, 14, 14, 19, 19, 15, 15, 15, 15, 15, 15, 15, 15, 17, 17, 17, 17, 17, 16, 16, 16, 16, 16, 16.

With this data:

1. Write the data sequentially

2. Put the data into a tally table

3. Then order it for a coding table ready to work out the mean and standard deviation

Use the following:

Chosen Value 15.000 N/mm˛

Unit Value: 1.0 N/mm˛