Statistics and Probability Answers

How many two-digits numbers can be made from the digits 6,7 and 8 if repetition of the digits is allowed

The manager of the machine-made kretek kretek cigarette company RAENAK found that 12% of its production was below production standards (poor). One day, the manager received a report that on that day 17% of substandard cigarette products were obtained from a random sample of 1000 cigarettes. Test whether the manufacturing defects (17%) are random or permanent (machines need to be repaired)! Use a= 0.05!

Manajer perusahaan rokok RAENAK sigaret kretek mesin mendapati bahwa 12% dari produksinya berada di bawah standar produksi (buruk). Pada suatu hari, manajer tersebut mendapatkan laporan bahwa pada hari tersebut didapatkan produk rokok di bawah standar sebesar 17% dari sampel acak sebesar 1000 batang rokok. Ujilah apakah cacat produksi (sebesar 17%) tersebut bersifat random atau permanen (mesin harus diperbaiki)! Gunakan a= 0,05! The manager of the machine-made kretek kretek cigarette company RAENAK found that 12% of its production was below production standards (poor). One day, the manager received a report that on that day 17% of substandard cigarette products were obtained from a random sample of 1000 cigarettes. Test whether the manufacturing defects (17%) are random or permanent (machines must be repaired)! Use a=0.05!

A company manufactures a new type of mosquito repellents with the period of effectiveness that is approximately normally distributed with a standard deviation of 30 hours. A sample of 40 repellents was taken and the average period of effectiveness is 290 hours. Calculate a 96% confidence interval for the true mean of the period of effectiveness

It is claimed that the average weight of a bag of biscuits is 250 grams with a standard deviation of 20.5 grams. Would you agree to this claim if a random sample of 30 bags of biscuits showed an average weight of 240 grams, What is the tabular value if the level of significance is 5%?

City planners wish to estimate the mean lifetime of the most commonly planted trees in urban settings. A sample of 16 recently felled trees yielded mean age 32.7 years with standard deviation 3.1 years. Assuming the lifetimes of all such trees are normally distributed, construct a 99.8% confidence interval for the mean lifetime of all such trees.

A random sample is drawn from a normally distributed population of known standard deviation 5. Construct a 99.8% confidence interval for the population mean based on the information given (not all of the information given need be used).

a. n = 16, 𝑥̅= 98, 𝑠 = 5.6

b. n = 9, 𝑥̅= 98, 𝑠 = 5.6