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Transcript les4e_alq_06ac
Active Learning Lecture Slides
For use with Classroom Response Systems
Chapter 6: Confidence Intervals
Elementary Statistics:
Picturing the World
Fourth Edition
by Larson and Farber
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 4- 1
A random sample of 42 textbooks has a
mean price of $114.50 and a standard
deviation of $12.30.
Find a point estimate for the mean price of
all textbooks.
A. $42
B. $12.30
C. $114.50
D. $2.73
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 2
A random sample of 42 textbooks has a
mean price of $114.50 and a standard
deviation of $12.30.
Find a point estimate for the mean price of
all textbooks.
A. $42
B. $12.30
C. $114.50
D. $2.73
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 3
Find the critical value zc necessary to form
a 98% confidence interval.
A. 2.33
B. 2.05
C. 0.5040
D. 0.8365
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 4
Find the critical value zc necessary to form
a 98% confidence interval.
A. 2.33
B. 2.05
C. 0.5040
D. 0.8365
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 5
A random sample of 42 textbooks has a
mean price of $114.50 and a standard
deviation of $12.30.
Find a 98% confidence interval for the
mean price of all textbooks.
A. (111.38, 117.62)
B. (110.08, 118.92)
C. (110.78, 118.22)
D. (109.61, 119.39)
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 6
A random sample of 42 textbooks has a
mean price of $114.50 and a standard
deviation of $12.30.
Find a 98% confidence interval for the
mean price of all textbooks.
A. (111.38, 117.62)
B. (110.08, 118.92)
C. (110.78, 118.22)
D. (109.61, 119.39)
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 7
Determine the minimum sample size needed
to construct a 95% confidence interval for the
mean age of employees at a company. The
estimate must be accurate to within 0.5 year.
Assume the standard deviation is 4.8 years.
A. 18
B. 19
C. 354
D. 355
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 8
Determine the minimum sample size needed
to construct a 95% confidence interval for the
mean age of employees at a company. The
estimate must be accurate to within 0.5 year.
Assume the standard deviation is 4.8 years.
A. 18
B. 19
C. 354
D. 355
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 9
Find the critical value tc necessary to form
a 95% confidence interval with a sample
size of 15.
A. 1.960
B. 2.145
C. 2.131
D. 2.120
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 10
Find the critical value tc necessary to form
a 95% confidence interval with a sample
size of 15.
A. 1.960
B. 2.145
C. 2.131
D. 2.120
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 11
A random sample of 15 DVD players has a
mean price of $64.30 and a standard
deviation of $5.60.
Find a 95% confidence interval for the
mean price of all DVD players.
A. (61.20, 67.40)
B. (61.47, 67.13)
C. (61.22, 67.38)
D. (61.10, 67.51)
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 12
A random sample of 15 DVD players has a
mean price of $64.30 and a standard
deviation of $5.60.
Find a 95% confidence interval for the
mean price of all DVD players.
A. (61.20, 67.40)
B. (61.47, 67.13)
C. (61.22, 67.38)
D. (61.10, 67.51)
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 13
In a survey of 250 Internet users, 195 have
high-speed Internet access at home.
Find a point estimate for the proportion of
all Internet users who have high-speed
Internet access at home.
A. 1.28
B. 0.78
C. 0.22
D. 195
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 14
In a survey of 250 Internet users, 195 have
high-speed Internet access at home.
Find a point estimate for the proportion of
all Internet users who have high-speed
Internet access at home.
A. 1.28
B. 0.78
C. 0.22
D. 195
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 15
In a survey of 250 Internet users, 195 have
high-speed Internet access at home.
Find a 90% confidence interval for the
proportion of all Internet users who have
high-speed Internet access at home.
A. (1.19, 1.38)
B. (0.728, 0.832)
C. (0.731, 0.829)
D. (0.737, 0.823)
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 16
In a survey of 250 Internet users, 195 have
high-speed Internet access at home.
Find a 90% confidence interval for the
proportion of all Internet users who have
high-speed Internet access at home.
A. (1.19, 1.38)
B. (0.728, 0.832)
C. (0.731, 0.829)
D. (0.737, 0.823)
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 17
You want to estimate, with 95% confidence,
the proportion of households with pets.
Your estimate must be accurate within 3%
of the population proportion. No
preliminary estimate is available. Find the
minimum sample size needed.
A. 1141
B. 3267
C. 1068
D. 1067
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 18
You want to estimate, with 95% confidence,
the proportion of households with pets.
Your estimate must be accurate within 3%
of the population proportion. No
preliminary estimate is available. Find the
minimum sample size needed.
A. 1141
B. 3267
C. 1068
D. 1067
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 19
Find the critical values and for a 98%
confidence interval when the sample size
is 25.
2
R
A. R2 2.492
L2 2.492
B. 2.326
2.326
2
R
2
L
2
L
C. R2 44.314 L2 11.524
D. 42.980 10.856
2
R
2
L
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 20
Find the critical values and for a 98%
confidence interval when the sample size
is 25.
2
R
A. R2 2.492
L2 2.492
B. 2.326
2.326
2
R
2
L
2
L
C. R2 44.314 L2 11.524
D. 42.980 10.856
2
R
2
L
Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley
Slide 6- 21