Question

The probability of an operator entering alphanumeric data incorrectly into a field in a database is equally likely. The random variable X is the number of fields on a data entry form with an error. The data entry form has 28 fields. Is X a discrete uniform random variable? Why or why not? (Please provide the mathematical details that lead to your answer.)

Answer 1

Since P(0) and P(1) have not the same values for the probability, X is not a discrete uniform random variable.

Explanation:

Probability of data to be correct: 0.5

Probability of data being incorrect: 0.5

The random variable X is the number of fields that have an error within the range of 28.

P(0) =
`0.5^2^8`

P(1) =
`^2^8\text{C}_1 * 0.5 * 0.5^2^7 = 28 * 0.5 ^2^8`