a) The production machines of a company produce metal discs of 200g. It is noted that the weight of the discs follows a normal distribution. To test the consistency of the machines, 20 discs are randomly selected and the mean weight is 205g while the standard deviation is 7g. What is the 99% confidence interval for the average weight of the selected discs? (b) A company launched a new model of golf ball. It claimed that the driving distance is at least 300m. A sample of 20 balls yields a sample mean of 295m and sample standard deviation of 8m. It is assumed that the driving distance is normally distributed. Conduct an appropriate hypothesis testing at the 0.05 level of significance. Is there evidence that the mean driving distance as claimed by the company is true?
(a) The production machines of a company produce metal discs of 200g. It is noted that the weight of the discs follows a normal distribution. To test the consistency of the machines, 20 discs are randomly selected and the mean weight is 205g while the standard deviation is 7g. What is the 99% confidence interval for the average weight of the selected discs?
(b) A company launched a new model of golf ball. It claimed that the driving distance is at least 300m. A sample of 20 balls yields a sample mean of 295m and sample standard deviation of 8m. It is assumed that the driving distance is
Conduct an appropriate hypothesis testing at the 0.05 level of significance. Is there evidence that the mean driving distance as claimed by the company is true?
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