Concept explainers
I need C only but you may need the A and B to get C.
A matched pairs experiment compares the taste of instant coffee with fresh-brewed coffee. Each subject tastes two unmarked cups of coffee, one of each type, in random order and states which he or she prefers. Of the 50 subjects who participate in the study, 19 prefer the instant coffee and the other 31 prefer fresh-brewed.
Let p be the proportion of the population that prefers fresh-brewed coffee.
a. Test the claim that a majority of people prefer the taste of fresh-brewed coffee. Report the z test-statistic and its p-value. Is your test result significant at the α = 10% level? What is your practical conclusion?
b. Use RStudio to perform the hypothesis testing with significance level α = 10%. Use the data set “COFFEE.xlsx or COFFEE.csv”
c. Find a 95% (not 90%) confidence interval for population proportion p.
Trending nowThis is a popular solution!
Step by stepSolved in 2 steps
- The Bureau of Labor Statistics reports that the official unemployment rate for Black people was 10.4% and 4.7% for White people in February 2015. Select all correct answers for this question. O The samples of white and black people are independent. The explanatory variable is the unemployment rate. The response variable is the unemployment rate. The response variable is race.arrow_forwardMany fundraisers ask for donations using email and text messages. A paper describes an experiment to investigate whether the proportion of people who make a donation when asked for a donation by email is different from the proportion of people who make a donation when asked for a donation in a text message. In this experiment, 1.7% of those who received and opened an email request for a donation and 7.8% of those who received a text message asking for a donation actually made a donation. Assume that the people who received these requests were randomly assigned to one of the two groups (email or text message) and suppose that the given percentages are based on sample sizes of 2,000 (the actual sample sizes in the experiment were much larger). (Let p1 be the proportion who make a donation after receiving an email, and p2 be the proportion who make a donation after receiving a text message.) Find the test statistic and P-value. (Use a table or SALT. Round your test statistic to two…arrow_forwardCaden then performs a significance test. First, he performs 100 simulations. For each simulation, he randomly reorganizes the subjects into two groups, A and B, of size 10. In the simulations, group A plays the role of the treatment group and group B plays the role of the control group. After each simulation, he subtracts the average for group B from the average for group A. The distribution of the differences for all 100 simulations is shown in the histogram. 30 28 26 24 22 12 10 6. 2 Group A avg. - Group B avg. In the original experiment, the average for the treatment group was 0.8 higher than the average for the control group. Based on the 100 simulations, are the results of the experiment significant at the 5% level? yes no Number of simulations [-2.7, -2.2) [-2.2, -1.7) [-1.7, -1.2) [-1.2, -0.7) [-0.7, -0.2) [-0.2, 0.3) [0.3, 0.8) [0.8, 1.3) [1.3, 1.8) [1.8, 2.3) [2.3, 2.8)arrow_forward
- Number of Flights Arriving on Time Number of Flights Arriving Late Sunshine Airline 33 5 Comfort Airlines 43 6 The table above contains data from a study of two airlines - Sunshine Airlines & Comfort Airlines - which fly from BWI to Shore City, FL. If one flight is selected, find P (on time and Comfort Airlines).arrow_forwardSuppose you were presented with the results of a study comparing two different training methods for basketball athletes. You are told 32 athletes were randomly assigned to the two groups so that 16 were in the group A and 16 were in the group B. At the end of the session, the average scores (wins versus losses) of the two groups/teams were compared and a difference of 10% was observed ( the first team had 10% more wins than the second). The coach observer reports two- sample t-test shows this difference is statistically significant. How would you interpret these findings? What questions or concerns would you have? How might this type of study be improved? Hint: Consider the possibility that the test performed was not the appropriate one.arrow_forwardA psychologist would like to examine the effects of a new drug on the activity level of animals. Three samples of rats are selected with n=5 in each sample. One group gets no drug, one group gets s small dose, and the third group gets a large dose. The psychologist records the activity level for each animal. The data from this experiment are presented below. No drug Small dose Large dose 5, 3 , 1 , 1 , 5 5, 5, 9, 6, 5 10, 12, 9, 6, 8 =3, SS=16 =6, SS=12 =9, SS=20 Do these data indicate any significant differences among the three groups? Test with α=0.05. Compute the effect size and interpret the result.arrow_forward
- Students at a major university believe they can save money buying textbooks online rather than at the local bookstores. In order to test this theory, they randomly sampled 25 textbooks on the shelves of the local bookstores. The students then found the "best" available price for the same textbooks via online retailers. The prices for the textbooks are listed in the following table. Based on the data, is it less expensive for the students to purchase textbooks from the online retailers than from local bookstores? Use a = 0.01. Let prices at local bookstores represent Population 1 and prices at online retailers represent Population 2. Textbook Bookstore 1 127 2 51 3 107 4 64 5 138 6 83 7 129 8 88 9 50 10 78 11 111 12 138 13 115 Textbook Prices (Dollars) Online Retailer Textbook 14 15 16 17 18 19 20 21 22 23 24 25 135 51 90 46 125 88 125 92 34 76 95 127 96 Bookstore 53 133 111 90 60 54 118 86 77 56 51 100 Online Retailer 61 130 126 93 67 68 99 84 58 46 34 109 Copy Data Step 2 of 3:…arrow_forwardMicah is interested in testing whether college students' levels of gratitude change over the course of the semester. He randomly selects a sample of 100 students and assesses their levels of gratitude at the beginning, and end of the semester. Question 17 options: ANOVA Paired samples t test Independent samples t test Correlationarrow_forwardDataset: NES. Variables: spend8, nesw.) The NES dataset contains spend8, which records the number of government policy areas where respondents think spending should be increased. Scores range from 0 (the respondent does not want to increase spending on any of the policies) to 8 (the respondent wants to increase spending on all eight policies). The NES, of course, polls a random sample of U.S. adults. In this exercise you will analyze spend8 using the Analyze ▶ Compare Means ▶ One-Sample T Test procedure. You then will draw inferences about the population mean. Make sure you weight observations using the nesw variable so your results are nationally representative. A. The spend8 variable has a sample mean of ______.arrow_forward
- A telephone service representative believes that the proportion of customers completely satisfied with their local telephone service is different between the South and the Midwest. The representative's belief is based on the results of a survey. The survey included a random sample of 11601160 southern residents and 12601260 midwestern residents. 43%43% of the southern residents and 56%56% of the midwestern residents reported that they were completely satisfied with their local telephone service. Find the 80%80% confidence interval for the difference in two proportions. Step 3 of 3 : Construct the 80%80% confidence interval. Round your answers to three decimal places.arrow_forwardThe director of student services at Oxnard College is interested in whether women are less likely to attend orlentation than men before they begin their coursework. A random sample of freshmen at Oxnard College were asked what their gender is and whether they attended orientation. The results of the survey are shown below: Data for Gender vs. Orlentation Attendance Women Men Yes 426 491 No 190 189 What can be concluded at the a = 0.10 level of significance? For this study, we should use Select an answer a. The null and alternative hypotheses would be: Ho: Select an answery Select an answerv Select an answerv (please enter a decimal and note that p1 and ul represent the proportion and mean for women and p2 and u2 represent the proportion and mean for men.) H: Select an answerv Select an answerv Select an answerv (Please enter a decimal) b. The test statistic ?v = (please show your answer to 3 decímal places.) c. The p-value = (Please show your answer to 4 decimal places.) d. The p-value…arrow_forwardA research study wanted to examine whether religious belief and gender are related in their state. They selected a representative sample of men and women in their State.Select the null and alternative hypothesis of the test: H0: there is no relationship between gender and belief about human originsHa: there is a relationship between gender and belief about human origins H0: there is a relationship between gender and belief about human originsHa: there is no relationship between gender and belief about human origins Results of the study are summarized in this table for the Belief about human origins: religious texts evolutionary theory total male 30 36 66 female 110 89 199 total 140 125 265 The degrees of freedom for the the ?2 statistic are Round the following numbers to two places after the decimal:The test statistic is ?2 = with a p-value = The conclusion of the test at the 5% significance level is There is not enough statistical evidence to suggest that gender…arrow_forward
- A First Course in Probability (10th Edition)ProbabilityISBN:9780134753119Author:Sheldon RossPublisher:PEARSON