Question 10pts Uploadyour work for questions 2 and 10 here. UploadChoose a FileFlag this Question Problems 2 - 9: A quality control engineer for a major toy company recently performed some statistical...

Question 10pts

Uploadyour work for questions 2 and 10 here.

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Problems 2 - 9:

A quality control engineer for a major toy company recently performed some statistical analysis on the length of plastic screws produced by its ‘Plastics Division'. These particular screws are used in the construction of certain children’s toys, so their length is important in the structural integrity of the toys. Thus, a check is periodically performed. He found that the mean length of the screws is3.5cm and the standard deviation is0.01cm.

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Draw a normal distribution curve of these screws by hand and be sure to be neat. You will need to show the mean, the values for plus or minus 1 standard deviation and 2 standard deviations, along with the rough and ready percentages that apply. Be sure to indicate, with label arrows, 1 and 2 standard deviations (see readings and lecture slides for example).
There is no need to show three standard deviations.

Did you uploadyour normal distribution curve at the beginning of this assignment?

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Assume the quality control engineer chooses one screw at random. What percentage of the time will the length of the screw be more than 3.51 cm?

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Assume the quality control engineer chooses one screw at random. What percentage of the time will the length of the screw be less than 3.48 cm?

Flag this QuestionQuestion 54pts

Assume the quality control engineer chooses one screw at random. What percentage of the time will the length of the screw be more than 3.49 cm?

Flag this QuestionQuestion 64pts

Assume the quality control engineer chooses one screw at random. What percentage of the time will the length of the screw be less than 3.52 cm?

Flag this QuestionQuestion 74pts

Assume the quality control engineer chooses one screw at random. What percentage of the time will the length of the screw be lessthan 3.5 cm?

Flag this QuestionQuestion 84pts

Assume the quality control engineer chooses one screw at random. What percentage of the time will the length of the screw be between 3.48 cm and 3.51 cm?

Flag this QuestionQuestion 94pts

Assume the quality control engineer chooses one screw at random. What percentage of the time will the length of the screw be between 3.51 cm and 3.52 cm?

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Problems 10 - 14:

The 911 emergency center in a certain city receives various numbers of calls on different days. A record of the center shows that the number of daily calls is normally distributed with the mean of 150 and standard deviation of 25.

Flag this QuestionQuestion 106pts

Draw a normal distribution curve of the 911 emergency centerscalls by hand and be sure to be neat. You will need to show the mean, the values for plus or minus 1 standard deviation and 2 standard deviations, along with the rough and ready percentages that apply. Be sure to indicate, with label arrows, 1 and 2 standard deviations (see readings and lecture slides for example).There is no need to show three standard deviations.

Did you uploadyour normal distribution curve at the beginning of this assignment?

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What percent of the days in this record have more than 100 calls?

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What percent of the days in this record have fewer than 175 calls?

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What percent of the days in this record have between 125 and 200 calls?

Flag this QuestionQuestion 143pts

What percent of the days in this record have more than 200 calls?

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Problems 15 - 17

Use the new formula from class to calculate the standard deviations.Standard deviations must be written as a percent. Round to one decimal point.
DO NOTround until the very end when finding the percent.
(Refer to page 5 in the readings.)

Flag this QuestionQuestion 154pts

Assume p = 54% and our sample size, n = 375.

Calculate thestandard deviation

Flag this QuestionQuestion 164pts

Assume p = 68% and our sample size, n = 1105.

Calculate thestandard deviation.

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Assume p = 4% and our sample size, n = 250

Calculate thestandard deviation.

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Problems 18 and 19:

The University of Michigan Survey Research Center conducted a survey of 2000 people in 1976. 20% of those surveyed said they felt unhappy about their jobs.

Flag this QuestionQuestion 184pts

Calculate thestandard deviationusing our new formula.Standard deviations must be written as a percent. Round to one decimal point.
DO NOTround until the very end when finding the percent.

Flag this QuestionQuestion 193pts

Find a 95% Confidence Interval for the true proportion of people who felt unhappy about their jobs.

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Problems 20 and 21:

In July 1998, the National Science Foundation commissioned a survey which revealed that vast numbers of American adults are scientifically illiterate. A Boston Globe article describing the results of this study reported that of 2041 adults questioned, only 72% knew the earth revolved around the sun and not the other way around!!!

Flag this QuestionQuestion 204pts

Calculate thestandard deviationusing our new formula.Standard deviations must be written as a percent. Round to one decimal point.
DO NOTround until the very end when finding the percent.

Flag this QuestionQuestion 213pts

Assuming this was a random sample of all American adults, find a 95% confidence interval for the true proportion of scientifically knowledgeable American adults.

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Problems 22 - 24:

Let us say four times as many American adults were surveyed bythe National Science Foundation. Refer to questions 19 and 20.

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Calculate thestandard deviationusing our new formula.Standard deviations must be written as a percent. Round to one decimal point.
DO NOTround until the very end when finding the percent.

Flag this QuestionQuestion 233pts

Assuming this was a random sample of all American adults, find a 95% confidence interval if the change if four times as many American adults were surveyed.

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What happens to the confidence interval when you have four times as many American adults surveyed?

Group of answer choicesThe confidence interval is narrower because the margin of error is cut in half when you quadruple the sample size.The confidence interval is wider because the margin of error is cut in half when you quadruple the sample size.Nothing happens to the confidence interval because the margin of error is so small.Flag this Question

Problems 25 - 27:

What if the size of the survey was one-fourth as large? ( 1/4 of 2041) Round to the nearest whole when finding the n value.

Flag this QuestionQuestion 253pts

Calculate thestandard deviationusing our new formula.Standard deviations must be written as a percent. Round to one decimal point.
DO NOTround until the very end when finding the percent.

Flag this QuestionQuestion 263pts

Assuming this was a random sample of all American adults, find a 95% confidence interval if only 1/4 as many American adults were surveyed.

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What happens to the confidence interval when you have a fourth as many American adults surveyed from the original amount?

Group of answer choicesThe confidence interval is wider because the margin of error doubles when you cut the sample size to ¼ of its original size.The confidence interval is narrower because the margin of error doubles when you cut the sample size to ¼ of its original size.The confidence interval is not affected.Flag this Question

Problems 28 and29:

The
Encyclopedia Britannica

reports that 8% (use this value for your mean=p) of all North American males have some form of red-green color blindness. Imagine that you take a random sample of 184 North American males.

Flag this QuestionQuestion 283pts

Calculate thestandard deviationusing our new formula.Standard deviations must be written as a percent. Round to one decimal point.
DO NOTround until the very end when finding the percent.

Flag this QuestionQuestion 293pts

What is the probability (as a percent) that in this sample over 10% of these people will be color blind?