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Can anyone please help me answer to question 5 from (A to C)?

I am suffering A LOT..

5. (a) Duracell Battery Company claims that their rechargeable batteries will charge at least (712 - () times before dying out and needing to be replaced. A sample of 10 rechargeable Duracell batteries are tested, and the number of charges of each before needing to be replaced is as follows: 670, 690, 800, 720, 660, 650, 560, 540, 600, 730. At 5% significance level, test whether Duracell Battery Company's claim is true. Assume that the distribution of the charges of a rechargeable battery are normally distributed. [7 marks] (b) The letter grades in a Statistics course are distributed as follows (where 50 = 5 times (): Grade A B C D F Frequency 4+ 50 18 32 20 16 Is there any evidence that the distribution of grades is uniform, at 5% level of significance? [6 marks] (c) To determine current attitudes of parents concerning whether or not teachers should take a mandatory COVID-19 test to teach at schools, a survey was conducted in four Hong Kong public schools. The following table gives the attitudes of 550 parents surveyed: School 1 School 2 |School 3 School 4 In Favor 65 66 40 34 Oppose 42 30 33 42 No Opinion 93 54 27 24 Test whether there is an association between the School and the attitude towards mandatory COVID- 19 test at 1% level of significance. [7 marks]