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5. Lachlan has calculated his mean mathematics score to be 67%, based on eight tests. If he s 75% on the ninth test, what will his new mean score be? 6. A shoe company surveyed the shoe size purchased by women over a period of time. The results were as follows: 8, 5, 6, 5, 8, 6, 7, 9, 5, 7, 6, 8, 8, 6, 9, 7, and 8. I (a) Calculate the mear an of this data (b) Find the modal value. (c) Find the median value. (d) Which of these values would be of the most use to the company? Why