Intro Stats
4th Edition
ISBN: 9780321825278
Author: Richard D. De Veaux, Paul F. Velleman, David E. Bock
Publisher: PEARSON
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Textbook Question
Chapter 21, Problem 16E
Friday the 13th, accidents The researchers in Exercise 15 also examined the number of people admitted to emergency rooms for vehicular accidents on 12 Friday evenings (6 each on the 6th and 13th).
Based on these data, is there evidence that more people are admitted, on average, on Friday the 13th? Here are two possible analyses of the data:
Paired t-Test of μ(1 – 2) = 0 vs. μ (1 – 2) < 0
t-Statistic = –2.7116 with 5 df
P = 0.0211
2-Sample t-Test of μ1 = μ2 vs. μ1 < μ2
Difference Between Means = –3.333
t-Statistic = –1.6644 with 9.940 df
P = 0.0636
- a) Which of these tests is appropriate for these data? Explain.
- b) Using the test you selected, state your conclusion.
- c) Are the assumptions and conditions for inference met?
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Chapter 21 Solutions
Intro Stats
Ch. 21.4 - Think about each of the situations described...Ch. 21.4 - Prob. 2JCCh. 21.4 - Are parents equally strict with boys and girls? In...Ch. 21.4 - Prob. 4JCCh. 21.4 - Prob. 5JCCh. 21 - SECTION 18.1 1. Which method? Which of the...Ch. 21 - Prob. 2ECh. 21 - SECTION 18.2 3. Cars and trucks We have data on...Ch. 21 - Prob. 4ECh. 21 - Prob. 5E
Ch. 21 - Prob. 6ECh. 21 - Blocking cars and trucks Thinking about the data...Ch. 21 - Prob. 8ECh. 21 - Prob. 9ECh. 21 - Prob. 10ECh. 21 - Prob. 11ECh. 21 - Freshman 15? Many people believe that students...Ch. 21 - Prob. 13ECh. 21 - Prob. 14ECh. 21 - Prob. 15ECh. 21 - Friday the 13th, accidents The researchers in...Ch. 21 - Prob. 17ECh. 21 - Prob. 18ECh. 21 - Prob. 19ECh. 21 - Wind speed, part II In Exercise 18, we saw summary...Ch. 21 - Prob. 21ECh. 21 - Prob. 22ECh. 21 - 23. Temperatures The following table gives the...Ch. 21 - Prob. 24ECh. 21 - Prob. 25ECh. 21 - Brain waves An experiment was performed to see...Ch. 21 - Prob. 27ECh. 21 - Prob. 28ECh. 21 - Prob. 29ECh. 21 - Prob. 30ECh. 21 - Stopping distance A tire manufacturer tested the...Ch. 21 - Stopping distance 60 For another test of the tires...Ch. 21 - Prob. 33ECh. 21 - Prob. 34ECh. 21 - Prob. 35ECh. 21 - Prob. 36ECh. 21 - Prob. 37ECh. 21 - 38. Marathon start-up years 2010 When we...Ch. 21 - BST Many dairy cows now receive injections of BST,...Ch. 21 - BST II In the experiment about hormone injections...
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