Download Quiz 11

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