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Three machines A, B and C produce respectively 50%, 30% and 20% of the total number of items of a factory. The percentage of defective output of these machines are 3%, 4% and 5% respectively. if an item selected at random, find the probability that the item is non-defective.
The average public elementary school has 468 students with a standard deviation of 87.If a random sample of 38 public elementary schools is selected,what is the probability that the number of students enrolled is between 445 and 485
A health specialist wants to determine the average number of hours a person
exercises in a day during the quarantine period. She found out that the mean number
of hours a person exercises in a day during the quarantine period is 80 minutes. A
random sample of 29 persons were surveyed and found that their mean is 65 minutes
and a standard deviation of 10 minutes. Test the hypothesis at 2% level of significance
and assume that the population is normally distributed.
A dart hits the circular dartboard shown below at a random point. Find the probability that the dart lands in the shaded square region. The radius of the dartboard is 9
in, and each side of the shaded region is 3in.
Two-tailed test; variance is known, alpha = 0.05 , n = 40
Number of occurrence of a tossing four coins
What is the computed z of the problem stated below?
The average monthly salary for a call center representative in the Philippines is P 21,700 with a standard deviation of P 6,000. Find the probability that a group of 64 randomly selected call center representatives has an average salary higher than P 22,000 per month.
The operations manager of a sugar mill in Durban wants to estimate the average size of an order by constructing a 90% confidence interval. An order is measured in the number of pallets shipped. A random sample of 87 orders from customers had an average of 131.6 pallets. Based on information from past records, the operations manager assumes that the number of pallets shipped is normally distributed with a standard deviation of 25 pallets.
What is the confidence interval constructed by the operations manager?
(Round off to the nearest whole numbers.)
Find the 90th. Percentile of the t-distribution if the sample size is 25?
2. The director of a secretarial school believes that its graduates can type more than75
words per minute. A random sample of 12 graduates has been found to have an
average of 77.2 words per minute with a standard deviation of 7.9 words per minute
in a typing test. Using the 0.05 level of significance, test the claim of the director.
