William had a six-sided dice numbered from 1 to 6. He rolled it a total of 50 times. It landed on an even number 23 times.

a) Work out the relative frequency of the dice landing on an even number. Give your answer as a decimal.
b) If the dice were fair, what would the theoretical probability of it landing on an even number be? Give your answer as a decimal.
c) Is the dice definitely biased or definitely not biased, or is it impossible to tell? Write a sentence to explain your answer.​