Concept explainers
For Exercises 1 through 25, perform each of the following steps.
a. State the hypotheses and identify the claim.
b. Find the critical value(s).
c. Compute the test value.
d. Make the decision.
e. Summarize the results.
Use diagrams to show the critical region (or regions), and use the traditional method of hypothesis testing unless otherwise specified.
1. Warming and Ice Melt The average depth of the Hudson Bay is 305 feet. Climatologists were interested in seeing if warming and ice melt were affecting the water level. Fifty-five measurements over a period of randomly selected weeks yielded a sample mean of 306.2 feet. The population variance is known to be 3.6. Can it be concluded at the 0.05 level of significance that the average depth has increased? Is there evidence of what caused this to happen?
Source: World Almanac and Book of Facts 2010
Trending nowThis is a popular solution!
Chapter 8 Solutions
Elementary Statistics: A Step By Step Approach
Additional Math Textbook Solutions
Statistical Techniques in Business and Economics
Introductory Statistics (10th Edition)
Essential Statistics
Elementary Statistics (13th Edition)
Developmental Mathematics (9th Edition)
Applied Statistics in Business and Economics
- Direction: Analyze each problem. Test the hypothesis by following the steps below. a. Null and alternative hypothesis. b. Level of Significance. c. Test statistic to be used and decide whether a one-tailed test or two-tailed test. d. Critical value and the rejection region/s. e. Compute for the value of the test statistic. f. State the decision. g. State the conclusion.arrow_forwardThe data show the number of vacation days used by a sample of 20 employees in a recent year. Use technology to answer parts (a) and (b). a. Find the data set's first, second, and third quartiles. b. Draw a box-and-whisker plot that represents the data set. 9 10 3 6 8 1 4 1 9 0 1 7 3 3 9 4 1 495 a. Find the three quartiles. = Q3 = (Type integers or decimals. Do not round.) b. Choose the correct answer plot below. Note that different technologies will produce slightly different results. O A. 0 3 6 9 B. 0 6 9 O C. 0 3 6 9 ✔arrow_forwardCloud seeding, a process in which chemicals such as silver iodide and frozen carbon dioxide are introduced by aircraft into clouds to promote rainfall was widely used in many years. Recent research has questioned its effectiveness. An experiment as performed by randomly assigning 52 clouds to be seeded or not. The amount of rain generated was then measured in acre-feet. The box plot of the data for the seeded and unseeded clouds are shown in the figure. Which statement best interprets the box plot. Boxplot of Seeded, Unseeded 3000 f 2500어 2000 - 1500 - 1000 - 500- Seeded Unseeded a. Cloud seeding is somewhat effective in promoting rainfall because of the greater mean b. Outliers for both seeded and unseeded data may prove data on the effectiveness of cloud seeding is insufficient c. Extreme outliers are evident in the seeded data and has greater variance O d. There's a greater mean and greater dispersion in the seeded data. Both plots show outliers Dataarrow_forward
- Instructions: Determine whether the statement below is a null hypothesis or an alternative hypothesis. Shade the box that corresponds to the correct answer. Activity Proper: Shade It! 1. The average age of grade eleven students is 17 years old. 2. The mean content of citric acid in a bottle of juice drinks is greater than 2 ml. 3. The average monthly salary of private school teachers is less than Php 16,000. 4. The mean weight of newborn babies is 0.5 kg. 5. The average IQ of grade eleven students is less than 108. 6. The average time to commute from home to school is 35.9 minutes. 7. The average number of vehicles passing through NLEX daily is less than 21,000. 8. The average daily number of customers in a convenient store is less than 1,025. 9. The average typing speed of a secretary is 23.8 words per minute. 10. The average weekly allowance of college students is less than Php 1,500. Null Hypothesis Null Hypothesis Null Hypothesis Null Hypothesis Null Hypothesis Null Hypothesis Null…arrow_forwardCloud seeding, a process in which chemicals such as silver iodide and frozen carbon dioxide are introduced by aircraft into clouds to promote rainfall was widely used in many years. Recent research has questioned its effectiveness. An experiment as performed by randomly assigning 52 clouds to be seeded or not. The amount of rain generated was then measured in acre-feet. The box plot of the data for the seeded and unseeded clouds are shown in the figure. Which statement best interprets the box plot. Boxplot of Seeded, Unseeded 3000 2500 - 2000- 1500 1000 500 Seeded Unseeded a. Outliers for both seeded and unseeded data may prove data on the effectiveness of cloud seeding is insufficient b. Cloud seeding is somewhat effective in promoting rainfall because of the greater mean c. There's a greater mean and greater dispersion in the seeded data. Both plots show outliers d. Extreme outliers are evident in the seeded data and has greater variance Dataarrow_forwardH. : p = 0.65 and H, : p > 0.65 where p= the proportion of students who were quarantined at some point during the Fall Semester of 2020. Identify the correct explanation for a Type Il error. O Conclude the percent was higher than 65%, but it was not higher. Conclude the percent was higher than 65% and it was higher. O Did not conclude the percent was higher than 65%, but it was higher. O Did not conclude the percent was higher than 65% and it was not higher.arrow_forward
- A. Clearly state an appropriate null hypothesis and an alternative hypothesis. B. What proportion of deaths occurred while the windows were set at a vertical orientation? C. What statistical test would you use to test the null hypothesis? D. Carry out the statistical test from part (c). Is there evidence that window angle affects the mortality rates of birds?arrow_forwardDetermine and o; from the given parameters of the population and sample size. H=31, o = 14, n = 26 =口 %3D (Round to three decimal places as needed.)arrow_forwardThe data show the number of vacation days used by a sample of 20 employees in a recent year. Use technology to answer parts (a) and (b). a. Find the data set's first, second, and third quartiles. b. Draw a box-and-whisker plot that represents the data set. 8 1 70 39 1 2 8 1 7 4 2 7 1 7 9 6 1 10 D a. Find the three quartiles. Q, = Q2 = Q3 = (Type integers or decimals. Do not round.) Incoarrow_forward
- The clarity and cut of a diamond are two of the four C's of diamond grading. (The other two are color and carat.) For a sample of diamonds, the accompanying table lists the clarity (related as internally flawless, IF, very very slightly included, VVS, very slightly included, VS, slightly included, Sl and included, I) for the two lowest ratings for cut, which are "good" and "fair". Complete parts a through c below. E Click the icon to view the table a. Find the conditional proportions for the five categories of clarity, given cut Clarity by Cut Clarity vs Cut IF SI Total Good 89 %3D Fair 53 (Round to thrce decimal places as needed.) b. Sketch (or create using software) a side-by-side (or stacked) bar graph that compares the two cuts on clarity. Summarize findings in a paragraph. Let the left bar for each clarity represent "good" cuts and the right bar represent "fair" cuts. Choose the correct answer below. O A. OB. Clarity for Good and Fair Diamonds 05 IF WS VS SII IF VVS vs SII OC.…arrow_forwardThe data show the number of vacation days used by a sample of 20 employees in a recent year. Use technology to answer parts (a) and (b). a. Find the data set's first, second, and third quartiles. b. Draw a box-and-whisker plot that represents the data set. 1 5 4 3 6 0 5 3 4 5 3 1 10 7 8 6 1 2 89 a. Find the three quartiles. Q₁ = Q₂ = Q3 = (Type integers or decimals. Do not round.) b. Choose the correct answer plot below. Note that different technologies will produce slightly different results. O A. OB. Q Q C O C. Qarrow_forwardA study was conducted at a local college to analyze the average cumulative GPA’s of students who graduated last year. Fill in the letter of the phrase that best describes each of the items below. The average cumulative GPA of students in the study who graduated from the college last year is? a. Data b. Sample c. Population d. Statistic e. Variable f. Parameterarrow_forward
- 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