The mean time to retrieve a record from an online database is 200 milliseconds with a standard deviation of 58 milliseconds

The mean time to retrieve a record from an online database is 200 milliseconds with a standard deviation of 58 milliseconds. The design criterion requires that at least 80% of all retrieval times must not differ from the mean by more that 75 milliseconds.

(a) Use Chebyshev’s inequality to establish whether the design criterion is satisfied.

(b) Would the design criterion be satisfied if it were known that the retrieval time is normally distributed with a mean of 200 milliseconds and a standard deviation of 58ms?