Probability & Statistics for Engineers & Scientists, MyLab Statistics Update (9th Edition)
9th Edition
ISBN: 9780134115856
Author: Ronald E. Walpole, Raymond H. Myers, Sharon L. Myers, Keying E. Ye
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Question
Chapter 8.8, Problem 53E
To determine
Check whether the variances of the two populations are equal or not.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Rothamsted Experimental Station (England) has studied wheat production since 1852. Each year many small plots of equal size but different soil/fertilizer conditions are planted with wheat. At the end of the growing season, the yield (in pounds) of the wheat on the plot is measured. Suppose for a random sample of years, one plot gave the following annual wheat production (in pounds):
4.46
4.21
4.40
4.81
2.81
2.90
4.93
3.54
4.16
4.48
3.26
4.74
4.97
4.02
4.91
2.59
Use a calculator to verify that the sample variance for this plot is . Another random sample of years for a second plot gave the following annual wheat production (in pounds):
3.89
3.81
3.95
4.07
4.01
3.73
4.02
3.78
3.72
3.96
3.62
3.76
4.02
3.73
3.94
4.03
Use a calculator to verify that the sample variance for this plot is . Suppose that we test the claim using that the population variance of annual wheat production for the first plot is larger…
It is thought that prehistoric Native Americans did not take their best tools, pottery, and household items when they visited higher elevations for their summer camps. It is hypothesized that archaeological sites tend to lose their cultural identity and specific cultural affiliation as the elevation of the site increases. Let x be the elevation (in thousands of feet) for an archaeological site in the southwestern United States. Let y be the percentage of unidentified artifacts (no specific cultural affiliation) at a given elevation. Suppose that the following data were obtained for a collection of archaeological sites in New Mexico:
x
5.50
6.00
6.75
7.00
7.75
y
37
38
92
70
99
Find the equation of the least squares line . Round a and b to three decimal places.
A fitness trainer wants to estimate the effect of fitness activities on muscle mass for different weight categories of club members. They choose the most popular fitness classes at the gym: yoga, circuit training, and high-intensity interval training (HIIT). Suppose that the weights of club members are separated into three levels: under 155 pounds, 155 – 200 pounds, and over 200 pounds. Draw a flow chart showing the design of this experiment.
Chapter 8 Solutions
Probability & Statistics for Engineers & Scientists, MyLab Statistics Update (9th Edition)
Ch. 8.2 - Define suitable populations from which the...Ch. 8.2 - The lengths of time, in minutes, that 10 patients...Ch. 8.2 - The reaction times for a random sample of 9...Ch. 8.2 - The number of tickets issued for traffic...Ch. 8.2 - The numbers of incorrect answers on a true-false...Ch. 8.2 - Prob. 6ECh. 8.2 - Prob. 7ECh. 8.2 - Prob. 8ECh. 8.2 - Prob. 9ECh. 8.2 - Prob. 10E
Ch. 8.2 - Prob. 11ECh. 8.2 - Prob. 12ECh. 8.2 - Prob. 13ECh. 8.2 - Show that the sample variance is unchanged if a...Ch. 8.2 - Prob. 15ECh. 8.2 - Prob. 16ECh. 8.4 - If all possible samples of size 16 are drawn from...Ch. 8.4 - Prob. 18ECh. 8.4 - A certain type of thread is manufactured with a...Ch. 8.4 - Given the discrete uniform population
find the...Ch. 8.4 - Prob. 21ECh. 8.4 - The heights of 1000 students are approximately...Ch. 8.4 - The random variable X, representing the number of...Ch. 8.4 - If a certain machine makes electrical resistors...Ch. 8.4 - The average life of a bread-making machine is 7...Ch. 8.4 - Prob. 26ECh. 8.4 - Prob. 27ECh. 8.4 - Prob. 28ECh. 8.4 - Prob. 29ECh. 8.4 - Prob. 30ECh. 8.4 - Prob. 31ECh. 8.4 - Prob. 32ECh. 8.4 - Prob. 33ECh. 8.4 - Prob. 34ECh. 8.4 - Consider the situation described in Example 8.4 on...Ch. 8.4 - Prob. 36ECh. 8.8 - For a chi-squared distribution, find
Ch. 8.8 - For a chi-squared distribution, find
Ch. 8.8 - For a chi-squared distribution, find such that
...Ch. 8.8 - For a chi-squared distribution, find such that
...Ch. 8.8 - Assume the sample variances to be continuous...Ch. 8.8 - Prob. 42ECh. 8.8 - Prob. 43ECh. 8.8 - Prob. 44ECh. 8.8 - Find P(T < 2.365) when v = 7.
Find P(T > 1.318)...Ch. 8.8 - Find P(−t0.005 < T < t0.01) for υ = 20.
Find P(T >...Ch. 8.8 - Given a random sample of size 24 from a normal...Ch. 8.8 - Prob. 48ECh. 8.8 - Prob. 49ECh. 8.8 - A maker of a certain brand of low-fat cereal bars...Ch. 8.8 - For an F-distribution, find
f0.05 with v1 = 7 and...Ch. 8.8 - Pull-strength tests on 10 soldered leads for a...Ch. 8.8 - Prob. 53ECh. 8.8 - Prob. 54ECh. 8.8 - Prob. 55ECh. 8.8 - Prob. 56RECh. 8.8 - Prob. 57RECh. 8.8 - Prob. 58RECh. 8.8 - Prob. 59RECh. 8.8 - A random sample of 5 bank presidents indicated...Ch. 8.8 - Prob. 61RECh. 8.8 - A taxi company tests a random sample of 10...Ch. 8.8 - Prob. 63RECh. 8.8 - Prob. 64RECh. 8.8 - Prob. 65RECh. 8.8 - Consider Review Exercise 8.56. Comment on any...Ch. 8.8 - Prob. 67RECh. 8.8 - Prob. 68RECh. 8.8 - Prob. 69RECh. 8.8 - Prob. 70RECh. 8.8 - Prob. 71RECh. 8.8 - Prob. 72RECh. 8.8 - Prob. 73RECh. 8.8 - Prob. 74RECh. 8.8 - Prob. 75RE
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.Similar questions
- The systolic blood pressure of individuals is thought to be related to both age and weight. Let the systolic blood pressure, age, and weight be represented by the variables x1, x2, and x3, respectively. Suppose that Minitab was used to generate the following descriptive statistics, correlations, and regression analysis for a random sample of 15 individuals. Descriptive Statistics Variable N Mean Median TrMean StDev SE Mean x 1 15 154.14 154.34 154.14 3.842 0.992000 x 2 15 59.69 60.19 59.69 1.462 0.377487 x 3 15 205.55 204.75 205.55 4.558 1.176871 Variable Minimum Maximum Q1 Q3 x 1 125 178 141.803 167.244 x 2 41 80 47.754 78.415 x 3 126 240 140.395 224.008 Correlations (Pearson) x 1 x 2 x 2 0.892 x 3 0.839 0.567 Regression Analysis The regression equation is x 1 = 0.883 + 1.257x2 + 0.871x3 Predictor Coef StDev T P Constant 0.883 0.635 1.39 0.095 x 2 1.257 0.635 1.98 0.036 x 3 0.871 0.419 2.08 0.030 S = 0.428 R-sq = 92.7 %…arrow_forwardAccording to health professionals, a person’s weight is expected to increase with age. To examine that statement, a nutritionist collected data from 11 random females from different age categories between the ages of 21 and 43. In the following table, x is the age of a person and y is the weight in pounds. x, age 21 24 27 29 31 33 35 38 40 42 43 y, weight in lb 121.4 122.3 130.3 131.7 133.3 134.6 136.7 138.4 140.3 142.0 145.1 Select the correct graph of the least-squares line on a scatter diagram.arrow_forwardLet x be a random variable that represents the percentage of successful free throws a professional basketball player makes in a season. Let y be a random variable that represents the percentage of successful field goals a professional basketball player makes in a season. A random sample of n = 6 professional basketball players gave the following information. x 82 69 73 84 74 64 y 42 48 46 46 46 42 Verify that ∑x =446, ∑y =270, ∑x2 =33,442, ∑y2 =12,180, ∑xy =20,070, and r = 0, and find the critical value for a test using a 5% level of significance claiming that ρis not equal than zero. Round your answer to three decimal places.arrow_forward
- Let x be a random variable that represents the percentage of successful free throws a professional basketball player makes in a season. Let y be a random variable that represents the percentage of successful field goals a professional basketball player makes in a season. A random sample of n = 6 professional basketball players gave the following information. x 75 72 75 81 74 81 y 46 39 42 47 49 50 Verify that Se ࣈ 3.591,a ࣈ –10.145, bࣈ0.729, and , and find the predicted percentage of successful field goals for a player with x= 88%successful free throws. Round your answer to the nearest tenth of a percentarrow_forwardAn editor wants to analyze if there is a significant difference in the ratings of books in four different genres. Random samples of book ratings were collected for four different genres. The editor recorded ratings in a 0 to 10 scale in the following table. Fiction Novel Biography Science&Technology 8.5 8.4 6.2 9.1 5.3 5.3 5.5 4.3 7.7 4.2 7.0 9.7 5.1 9.8 9.3 5.2 6.9 8.6 6.7 7.9 4.8 7.1 6.9 8.4 Shall we reject or not reject the claim that there are no differences among the population means of book ratings for the different genres? Use.arrow_forwardPeggy conducted a study to identify the randomness of rainy days in fall. For 15 days, she recorded whether it rained that day or not. They denoted a rainy day with the letter R, a day without rain with the letter N. R N N R R N N R R N N R R R R Test the sequence for randomness. Use .arrow_forward
- Consider the grades for the math and history exams for 10 students on a scale from 0 to 12 in the following table. Student Math History 1 4 8 2 5 9 3 7 9 4 12 10 5 10 8 6 8 5 7 9 6 8 9 6 9 11 9 10 7 10 Compute the Spearman correlation coefficient. Round your answer to three decimal places.arrow_forwardTo compare two elementary schools regarding teaching of reading skills, 12 sets of identical twins were used. In each case, one child was selected at random and sent to school A, and his or her twin was sent to school B. Near the end of fifth grade, an achievement test was given to each child. The results follow: Twin Pair 1 2 3 4 5 6 School A 169 157 115 99 119 113 School B 123 157 112 99 121 122 Twin Pair 7 8 9 10 11 12 School A 120 121 124 145 138 117 School B 153 90 124 140 142 102 Suppose a sign test for matched pairs with a 1% level of significance is used to test the hypothesis that the schools have the same effectiveness in teaching reading skills against the alternate hypothesis that the schools have different levels of effectiveness in teaching reading skills. Let p denote portion of positive signs when the scores of school B are subtracted from the corresponding scores of school…arrow_forwardA horse trainer teaches horses to jump by using two methods of instruction. Horses being taught by method A have a lead horse that accompanies each jump. Horses being taught by method B have no lead horse. The table shows the number of training sessions required before each horse performed the jumps properly. Method A 25 23 39 29 37 20 Method B 41 21 46 42 24 44 Method A 45 35 27 31 34 49 Method B 26 43 47 32 40 Use a rank-sum test with a5% level of significance to test the claim that there is no difference between the training sessions distributions. If the value of the sample test statistic R, the rank-sum, is 150, calculate the P-value. Round your answer to four decimal places.arrow_forward
- A data processing company has a training program for new salespeople. After completing the training program, each trainee is ranked by his or her instructor. After a year of sales, the same class of trainees is again ranked by a company supervisor according to net value of the contracts they have acquired for the company. The results for a random sample of 11 salespeople trained in the last year follow, where x is rank in training class and y is rank in sales after 1 year. Lower ranks mean higher standing in class and higher net sales. Person 1 2 3 4 5 6 x rank 8 11 2 4 5 3 y rank 7 10 1 3 2 4 Person 7 8 9 10 11 x rank 7 9 10 1 6 y rank 8 11 9 6 5 Using a 1% level of significance, test the claim that the relation between x and y is monotone (either increasing or decreasing). Verify that the Spearman rank correlation coefficient . This implies that the P-value lies between 0.002 and 0.01. State…arrow_forwardSand and clay studies were conducted at a site in California. Twelve consecutive depths, each about 15 cm deep, were studied and the following percentages of sand in the soil were recorded. 34.4 27.1 30.8 28.0 32.2 27.6 32.8 25.2 31.4 33.5 24.7 28.4 Converting this sequence of numbers to a sequence of symbols A and B, where A indicates a value above the median and B denotes a value below the median gives ABABABABAABB. Test the sequence for randomness about the median with a 5% level of significance. Verify that the number of runs is 10. What is the upper critical value c2? arrow_forwardSand and clay studies were conducted at a site in California. Twelve consecutive depths, each about 15 cm deep, were studied and the following percentages of sand in the soil were recorded. 34.4 27.1 30.8 28.0 32.2 27.6 32.8 25.2 31.4 33.5 24.7 28.4 Converting this sequence of numbers to a sequence of symbols A and B, where A indicates a value above the median and B denotes a value below the median gives ABABABABAABB. Test the sequence for randomness about the median with a 5% level of significance. Verify that the number of runs is 10. What is the upper critical value c2?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons Inc
Probability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage Learning
Statistics 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:PEARSON
The Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. Freeman
Introduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman
MATLAB: An Introduction with Applications
Statistics
ISBN:9781119256830
Author:Amos Gilat
Publisher:John Wiley & Sons Inc
Probability and Statistics for Engineering and th...
Statistics
ISBN:9781305251809
Author:Jay L. Devore
Publisher:Cengage Learning
Statistics for The Behavioral Sciences (MindTap C...
Statistics
ISBN:9781305504912
Author:Frederick J Gravetter, Larry B. Wallnau
Publisher:Cengage Learning
Elementary Statistics: Picturing the World (7th E...
Statistics
ISBN:9780134683416
Author:Ron Larson, Betsy Farber
Publisher:PEARSON
The Basic Practice of Statistics
Statistics
ISBN:9781319042578
Author:David S. Moore, William I. Notz, Michael A. Fligner
Publisher:W. H. Freeman
Introduction to the Practice of Statistics
Statistics
ISBN:9781319013387
Author:David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:W. H. Freeman
The Shape of Data: Distributions: Crash Course Statistics #7; Author: CrashCourse;https://www.youtube.com/watch?v=bPFNxD3Yg6U;License: Standard YouTube License, CC-BY
Shape, Center, and Spread - Module 20.2 (Part 1); Author: Mrmathblog;https://www.youtube.com/watch?v=COaid7O_Gag;License: Standard YouTube License, CC-BY
Shape, Center and Spread; Author: Emily Murdock;https://www.youtube.com/watch?v=_YyW0DSCzpM;License: Standard Youtube License