A lathe is set to cut bars of steel into lengths of 6 centimeters. The lathe is considered to be in perfect adjustment if the average length of the bars it cuts is 6 centimeters. A sample of 144 bars is selected randomly and measured. It is determined that the average length of the bars in the sample is 6.09 centimeters with a standard deviation of .48 centimeters.a. Formulate the hypotheses to determine whether or not the lathe is in perfect adjustment.b. Compute the test statistic.c. Using the p-value approach, what is your conclusion? Let ? = .05.How do you compute using excel?

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general 9 months ago 5803

An article in American Demographics claims that more than twice as many shoppers are out shopping on the weekends that during the week. Not only that, such shoppers also spend more money on their purchases on Saturdays and Sundays! Suppose that the amount of money spent at shopping centers between 4 P.M. and 6 P.M. on Sundays has a normal distribution with mean $85 and with a standard deviation of $20. A shopper is randomly selected on a Sunday between 4 P.M. and 6 P.M. and asked about his spending patterns.a. What is the probability that he has spent more than $95 at the mall?b. What is the probability that he has spent between $95 and $115 at the mall?c. If two shoppers are randomly selected, what is the probability that both shoppers have spent more than $115 at the mall?

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general 9 months ago 6057

​A researcher selects a sample from a population with μ = 30 and uses the sample to evaluate the effect of a treatment. After treatment, the sample has a mean of M = 32 and a variance of s2 = 6. Which of the following would definitely increase the likelihood of rejecting the null hypothesis?Question options:a.​Decrease the sample varianceb.​Increase the sample meanc.​Increase the sample sized.​All of the other options will increase the likelihood of rejecting the null hypothesis

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general 9 months ago 3260