QUESTION 3 [TOTAL MARKS: 20) (a) To determine the average speed of cars along a certain road, a random sample of 100 car

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Question 3 Total Marks 20 A To Determine The Average Speed Of Cars Along A Certain Road A Random Sample Of 100 Car 1 (55.1 KiB) Viewed 33 times

QUESTION 3 [TOTAL MARKS: 20) (a) To determine the average speed of cars along a certain road, a random sample of 100 cars is taken and the mean speed in the sample is found to be 58.4 mph. If the true standard deviation of the speeds is known to be 15 mph, find a 95% confidence interval for y, the true average speed. 18 marks) (b) A manufacturer of sports equipment has developed a new synthetic fishing line that is claimed to have a mean breaking strenght of 8 kg. To test the manufacturer's claim, that is, whether the mean breaking strenght is actually 8 kg or not, a sample of 12 lines is tested. The sample had a mean breaking strength of 7.8 kg and a standard deviation of 0.5 kg. Write down your null hypothesis and alternative hypothesis and then, using an appropriate distribution, test your null hypothesis against your alternative hypothesis at the 5% significance level. (12 marks]