Questions from Statistics Principles


Q: Suppose that Dunlop Tire manufactures a tire with a lifetime that approximately

Suppose that Dunlop Tire manufactures a tire with a lifetime that approximately follows a normal distribution with mean 70,000 miles and standard deviation 4400 miles. (a) What proportion of the tires...

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Q: A cellular phone company is looking for ways to improve customer satisfaction

A cellular phone company is looking for ways to improve customer satisfaction. They want to select a simple random sample of four stores from their 15 franchises in which to conduct customer satisfact...

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Q: The Wechsler Intelligence Scale for Children is approximately normally distributed, with

The Wechsler Intelligence Scale for Children is approximately normally distributed, with mean 100 and standard deviation 15. (a) What is the probability that a randomly selected test taker will score...

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Q: A congresswoman wants to survey her constituency regarding public policy. She

A congresswoman wants to survey her constituency regarding public policy. She asks one of her staff members to obtain a sample of residents of the district. The frame she has available lists 9012 Demo...

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Q: According to Major League Baseball rules, the ball must weigh between

According to Major League Baseball rules, the ball must weigh between 5 and 5.25 ounces. A factory produces baseballs whose weights are approximately normally distributed, with mean 5.11 ounces and st...

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Q: A farmer has a 500-acre orchard in Florida. Each

A farmer has a 500-acre orchard in Florida. Each acre is subdivided into blocks of 5. Altogether, there are 2500 blocks of trees on the farm. After a frost, he wants to get an idea of the extent of th...

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Q: According to a Gallup poll, 46% of Americans 18 years

According to a Gallup poll, 46% of Americans 18 years old or older stated that they had read at least six books (fiction and nonfiction) within the past year. You conduct a random sample of 250 Americ...

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Q: A casino manager wants to inspect a sample of 14 slot machines

A casino manager wants to inspect a sample of 14 slot machines in his casino for quality-control purposes. There are 600 sequentially numbered slot machines operating in the casino. Obtain a systemati...

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Q: A school psychologist wants to test the effectiveness of a new method

A school psychologist wants to test the effectiveness of a new method for teaching reading. She recruits 500 first-grade students in District 203 and randomly divides them into two groups. Group 1 is...

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Q: Use the results in the table to (a) draw

Use the results in the table to (a) draw a normal plot, (b) determine the linear correlation between the observed values and expected z-scores, (c) determine the critical value in Table VI to assess...

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