Concept explainers
(a)
whether the test scores have been selected from a normal population using a stem and leaf plot.
(a)
Answer to Problem 10.4E
Yes, the test scores have been selected from a normal population
Explanation of Solution
Given:
The below table describes the test scores on a 100-point test for 20 students:
Calculation:
Stem and leaf plot:
Draw a vertical line
Place the digits of the tens to the left of the vertical line and the digits of the ones of every data value to the right of the vertical line
stem | leaf |
5 | 7 |
6 | 2 5 7 8 |
7 | 1 2 3 5 5 6 7 |
8 | 2 4 4 6 6 9 |
9 | 1 3 |
It is reasonable to assume that the test scores have been selected from a normal population, because most of the data values lie roughly in the middle of the distribution indicating a symmetric distribution and there are no outliers visible (data values that are separated from the other data values with a gap.)
Conclusion:
Hence, yes, the test scores have been selected from a normal population
(b)
To Calculate: the mean and standard deviation of the scores
(b)
Answer to Problem 10.4E
The mean of the test scores is
The standard deviation of the test scores is
Explanation of Solution
Given:
The below table describes the test scores on a 100-point test for 20 students:
Calculation:
The mean of the test scores is
The variance of test scores is
The standard deviation of the test scores is
Conclusion:
Hence, the mean of the test scores is
(c)
To find: the
(c)
Answer to Problem 10.4E
The
Explanation of Solution
Given:
The below table describes the test scores on a 100-point test for 20 students:
Calculation:
If we choose a
The critical value is
A
Conclusion:
Hence, the
Want to see more full solutions like this?
Chapter 10 Solutions
Introduction to Probability and Statistics
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
- Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSONThe Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. FreemanIntroduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman