a) A fast-food restaurant offers only 4 choices of fast food, A, B, C and D. Past history shows that 25%, 25%, 25% and 25% customers chose A, B, C and D respectively. Now the restaurant has changed the cook, while the menu remains the same. In a random sample of 320 customers, 120, 60, 60 and 80 chose A, B, C and D respectively. Can we still conclude that equal proportion of customer choose different options? Observed A B C D Total Values 120 60 60 80 320 expected value Based on these data, can we still conclude that equal proportion of customer choose the different options? Use a 5% level of significance