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Practice Quiz 11.1 AP Statistics Name: At the bakery where you work, loaves of bread are supposed to weigh 1 pound. From experience, the weights of loaves produced at the bakery follow a Normal distribution with standard deviation = 0.13 pounds. You believe that new personnel are producing loaves that are heavier than 1 pound. As supervisor of Quality Control, you want to test your claim at the 5% significance level. You weigh 20 loaves and obtain a mean weight of 1.05 pounds. 1. Identify the population and parameter of interest. State your null and alternative hypotheses. 2. Identify the statistical procedure you should use. Then state and verify the conditions required for using this procedure. 3. Calculate the test statistic and the P-value. Illustrate using the graph provided. . 50 - 3. 0 3 .0 - . 50 4. State your conclusions clearly in complete sentences. Chapter 11 Practice Quiz 11.1 and 11.2 Statistics can help decide the authorship of literary works. Sonnets by an Elizabethan poet are known to contain an average of = 6.9 new words (words not used in the poet’s other works). The distribution of new words in this poet’s sonnets is Normal with standard deviation = 2.7. Now a manuscript with five new sonnets has come to light, and scholars are debating whether it is the poet’s work. The new sonnets contain an average of x = 9.2 words not used in the poet’s known works. We expect poems by another author to contain more new words than found in the Elizabethan poet’s poems. 5. Identify the population and parameter of interest. State appropriate hypotheses in both words and symbols. 6. Identify the appropriate statistical procedure and verify conditions for its use. 7. Calculate the test statistic and the P-value. Illustrate using the graph provided. .50 -3.0 3 .0 -.50 8. State your conclusions clearly in complete sentences. Chapter 11 Practice Quiz 11.1 and 11.2 The time needed for college students to complete a certain paper-and-pencil maze follows a Normal distribution with mean 30 seconds and standard deviation 3 seconds. You wish to see if the mean time is changed by vigorous exercise, so you have a randomly selected group of 9 students from a particular college exercise vigorously for 30 minutes and then complete the maze. It takes them an average of x 31.2 seconds to complete the maze. 9. Identify the population and parameter of interest. State appropriate hypotheses in both words and symbols. 10. Identify the appropriate statistical procedure and verify conditions for its use. 11. Calculate the test statistic and the P-value. Illustrate using the graph provided. .50 -3.0 3 .0 -.50 12. State your conclusions clearly in complete sentences. Chapter 11 Practice Quiz 11.1 and 11.2 13. Does the use of fancy type fonts slow down the reading of text on a computer screen? Adults can read four paragraphs of text in an average time of 22 seconds in the common Times New Roman font. Ask 25 adults to read this text in the ornate font named Gigi. Here are their times: 23.2 34.2 31.5 21.2 23.9 24.6 28.9 26.8 23.0 27.7 20.5 28.6 29.1 34.3 24.4 27.3 21.4 28.1 16.1 32.6 41.3 22.6 26.2 25.6 34.1 Suppose that reading times are Normal with = 6 seconds. Is there good evidence that the mean reading time for Gigi is greater than 22 seconds? Carry out an appropriate test to help you answer this question. Chapter 11 Practice Quiz 11.1 and 11.2 14. Your friend uses Minitab to generate 25 observations at random from a Normal distribution with known mean and standard deviation. Unfortunately, he forgot to save the file. He remembers that the standard deviation was 4, and he thinks that the mean was 20. Before he closed the program, your friend did manage to print the following output. Descriptive Statistics: rand Variable rand N 25 Mean 18.792 Median 18.663 TrMean 18.791 Variable rand Minimum 11.192 Maximum 26.422 Q1 17.223 Q3 21.128 StDev 3.241 SE Mean 0.648 Use an appropriate test to determine whether you believe your friend’s claim that the mean was 20. Chapter 11 Practice Quiz 11.1 and 11.2