A concrete pavement between interstate is required to be evaluated in terms of the reliability index. This section of concrete pavement has a mean strength of $40$ MPa and a standard deviation of $1\mathrm{.}5$ MPa. The asset owner has decided to measure the strength of this concrete pavement and found that the strength from different locations is $34$ Mpa, $36$ MPa and $35$ Mpa. Determine the reliability index. $($Note: NORMSINV function in Excel can be used to define the reliability index$).$