![The frequency distribution of the compressive strength of 20 concrete cube specimens is given in the table](https://www.gkseries.com/blog/wp-content/uploads/2023/09/The-frequency-distribution-of-the-compressive-strength-of-20-concrete-cube-specimens-is-given-in-the-table.jpg)
Q. The frequency distribution of the compressive strength of 20 concrete cube specimens is given in the table.
f (MPa) | Number of specimens with compressive strength equal to f |
23 | 4 |
28 | 2 |
22.5 | 5 |
31 | 5 |
29 | 4 |
If π is the mean strength of the specimens and π is the standard deviation, the number of specimens (out of 20) with compressive strength less than π β 3π is
Ans: 0
Sol:
Mean strength,
![](https://www.gkseries.com/blog/wp-content/uploads/2023/09/Screenshot-910.png)
β΄Β Number of specimen with compressive strength less than 15.485 MPa are zero.