Laboratory data show that the time required to complete two chemical reactions in a production process varies. the first reaction has a mean time of 40 minutes and a standard deviation of 2 minutes; the second has a mean time of 25 minutes and a standard deviation of 1 minute. the two reactions are run in sequence during production. there is a period of 5 minutes between the two reactions as the product of the first reaction is pumped into the vessel where the second reaction will take place.a. what is the mean time required for the entire process?b. what is the standard deviation of the combined process?

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general 11 months ago 5083

Here are summary statistics for randomly selected weights of newborn​ girls: nequals161​, x overbarequals32.8 ​hg, sequals7.2 hg. construct a confidence interval estimate of the mean. use a 90​% confidence level. are these results very different from the confidence interval 31.7 hgless thanmuless than34.5 hg with only 12 sample​ values, x overbarequals33.1 ​hg, and sequals2.7 ​hg? what is the confidence interval for the population mean mu​? 31.6 hgless thanmuless than 34.6 hg ​(round to one decimal place as​ needed.)

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general 11 months ago 8940

In your stor 155 class, the professor returns midterm 2 and claims that the average score was 83 out of 100 with a standard deviation of 8 points. when the professor steps out of the room, you quickly select a simple random sample of students (all students are present that day) and note their scores: 68, 75, 88, 79, 78, 79, 65, 77, 85, 71a.you strongly suspect that the professor is overstating the average so that students will blame themselves if they have a low midterm score. state the null and alternative hypotheses for the appropriate test of significance at α=0.05.

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general 11 months ago 7984

In a large​ city, 6060​% of people pass the​ drivers' road test. suppose that every​ day, 300300 people independently take the test. complete parts​ (a) through​ (d) below.a. what is the number of people who are expected to​ pass? the expected number is 180180. ​(round to the nearest whole number as​ needed.)b. what is the standard deviation for the number expected to​ pass? the standard deviation is nothing. ​(round to the nearest whole number as​ needed.)c. after a great many​ days, according to the empirical​ rule, on about​ 95% of these​ days, the number of people passing will be as low as​ _____ and as high as​ _____. (hint: find two standard deviations below and two standard deviations above the​ mean.) after a great many​ days, according to the empirical​ rule, on about​ 95% of these​ days, the number of people passing will be as low as nothing and as high as nothing. ​(round to the nearest whole number as​ needed.)d. if you found that one​ day, 134134 out of 300300 passed the​ test, would you consider this to be a very lowlow ​number? ▼ yes, no, because 134134 is ▼ less than 1 standard deviation between 1 and 2 standard deviations between 2 and 3 standard deviations more than 3 standard deviations belowbelow the mean.

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general 11 months ago 2664

Kyran was given a check for $100 by his grandmother for his birthday, but had to promise her that he would invest the money in a bank until it had at least doubled in value. Kyran agreed, reluctantly, and found a bank where he could invest the $100 in a simple interest account that would gain 5% interest per year. If represents the number of years that Kyran will invest his money, which inequality could be used to find when he would have at least $200 in his account?

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general 11 months ago 4455