Submit Assignment 11 | Gradescope 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 1 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new 0/21 Questions Answered...

Statistics homework help


Submit Assignment 11 | Gradescope 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 1 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new 0/21 Questions Answered Assignment 11 Q1 22 Points Are mosquitoes attracted differently to beer drinkers than to water drinkers? In a study using 43 college age volunteers, each subject was randomly assigned either to drink 350 ml of beer (5.5% alcohol) or the same amount of water. Researchers then counted the number of mosquito bites they received while sitting for ten minutes in a screen tent containing hundreds of hungry mosquitoes. The summary statistics are below. Assume neither distribution of number of mosquito bites has outliers. Beer: Water: Q1.1 Variable type and role P1 1 Point Fill in the blanks with one option in each set of parentheses to complete the description of the variable. Number of mosquito bites is the (explanatory/response) Enter your answer here and it is (categorical/quantitative) =xb 23.6, s =b 2.6, n =b 25 =xw 19.2, s =w 3.1, n =w 18 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 2 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new Enter your answer here Save Answer Q1.2 Variable type and role P2 1 Point Fill in the blanks with one option in each set of parentheses to complete the description of the variable. Type of drink is the (explanatory/response) Enter your answer here and it is (categorical/quantitative) Enter your answer here Save Answer Q1.3 Study design 1 Point What type of study design was used? Observational study because these data are from college age volunteers. ! Randomized experiment because these data are from college age volunteers. ! Observational study because the number of mosquito bites was observed, not randomly assigned. ! 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 3 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new Save Answer Q1.4 Parameter 1 Point Select the appropriate parameter of interest in words and notation. Save Answer Q1.5 Alternative hypothesis 1 Point Before conducting the experiment, scientists did not know if beer would attract or repel mosquitoes. What is the alternative hypothesis? Randomized experiment because the type of drink was randomly assigned. ! = the effect of drinking beer or water on the number of mosquito bites. ! µ −b µw = the difference in true proportion of people bitten by mosquitos when drinking beer versus water. ! π −b πw = the difference in mean number of mosquito bites after drinking beer versus after drinking water in this sample. ! −xb xw = the difference in true mean number of mosquito bites after drinking beer versus after drinking water. ! µ −b µw ! µ −b µ w 0 ! −xb >xw 0 Yes, the data comes from a randomized experiment.! Yes, the data comes from two random samples.! No, this study was conducted on 43 college age volunteers.! No, these data are paired.! 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 5 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new Q1.8 Calculations 4 Points a) Calculate the standard error of the difference in sample means. Show your work and round your answer to three decimal places. Enter your answer here b) Use your answer to part (a) to calculate the standardized statistic. Show your work and round your answer to three decimal places. Enter your answer here Save Answer Q1.9 Interpret standardized statistic 1 Point If your calculated standardized statistic was 2 (this is not the correct standardized statistic), which of the following would be the correct interpretation of that value? On average, each difference in mean number of mosquito bites from one sample is 2 away from 0. ! The probability of obtaining the observed difference in mean number of mosquito bites or something more extreme is 2/1000, assuming the true difference in mean number of mosquito bites is 0. ! The sample difference in mean number of mosquito bites is 2 standard errors above 0. ! The sample difference in mean number of mosquito bites is 2 mosquito bites above 0. ! 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 6 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new Save Answer Q1.10 P-value 1 Point What distribution should we compare the standardized statistic to in order to obtain the p-value for this test? Save Answer Q1.11 Conclusion 2 Points Using R , a p-value of 0.0008 was calculated. Using this value, write a conclusion in the context of the problem. Enter your answer here Save Answer Q1.12 Scope of infence 2 Points Fill in the blanks with one option in each set or parentheses to mosquito bites above 0. ! tdf=17 ! tdf=24 ! tdf=42 Standard Normal ( )! N(0, 1) 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 7 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new Fill in the blanks with one option in each set or parentheses to determine the appropriate scope of inference for this problem. From these data, we can determine (causal/non-causal) Enter your answer here inference and apply the results to (the population/those similar to the sample) Enter your answer here Save Answer Q1.13 Confidence interval R inputs 1 Point Suppose you need to create a 99% bootstrap confidence interval for these data. What arguments would you use in the two_mean_bootstrap_CI function in R ? formula = ( drink~bites / bites~drink ) Note: should be of the form response~explanatory Enter your answer here confidence_level = (#) Note: should be written as a decimal Enter your answer here Save Answer 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 8 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new Q1.14 Create 1 resample 1 Point How could we use cards to create one bootstrap resample by hand? Save Answer Q1.15 Center of confidence interval Have 43 cards and label each card with the number of mosquito bites for one participant. Shuffle the cards and deal them into two groups of size 25 and 18. Plot the difference in the mean number of mosquito bites (group size 25 – group size 18). ! Have 25 black cards and 18 red cards. On each card write the number of mosquito bites by one participant (beer drinkers on black cards, water drinkers on red cards). Draw with replacement 25 times from the black cards and 18 times from the red cards. Plot the difference in mean number of mosquito bites (group size 25 – group size 18). ! Have 25 black cards and 18 red cards. On each card write the number of mosquito bites by one participant (beer drinkers on black cards, water drinkers on red cards). Shuffle all the cards together and deal them into two groups of size 25 and 18. Plot the difference in the mean number of mosquito bites (group size 25 – group size 18). ! Have 25 black cards and 18 red cards. On each card write the number of mosquito bites by one participant (beer drinkers on black cards, water drinkers on red cards). Shuffle all the cards together and draw with replacement 25 times to create one group and 18 times to create a second group. Plot the difference in the mean number of mosquito bites (group size 25 - group size 18. ! 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 9 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new 1 Point What value would you expect to be at the center of the confidence interval? Save Answer Q1.16 Confidence interval R output 1 Point Below is the bootstrap distribution created in R using 3000 resamples. How many of the 3000 resamples are below the lower end-point of the interval shown at the bottom of the plot? Enter your answer here Save Answer The null value = 0! The sample statistic = 4.4! The p-value = 0.0008! The confidence level = 0.99! 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 10 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new Save Answer Q1.17 Confidence interval interpretation 1 Point Which of the following are correct and complete interpretations of the confidence interval shown in the R output provided above? Select all that apply. Save Answer We can be 99% confident that the true mean number of mosquito bites for beer drinkers is higher than for water drinkers by between 1.787 and 6.112 bites. Between 1.787% and 6.112% of beer drinkers had more mosquito bites than water drinkers. 99% of all beer drinkers were bitten between 1.787 and 6.112 more times than all water drinkers. The difference in mean number of mosquito bites in the population of beer and water drinkers is between 1.787 and 6.112 bites (beer – water), with 99% confidence. We are 99% confident that the true proportion of beer drinkers who were bitten more times than water drinkers is between 1.787% and 6.112%. We can say with 99% confidence that the long-run difference in mosquito bites between beer and water drinkers is between 1.787 bites and 6.112 bites, on average. 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 11 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new Q2 Out-of-class Activity 11 1 Point #4) In the out-of-class portion of Activity 11, explain why we multiplied by 2 in the R code to obtain the theoretical p-value. Enter your answer here Save Answer Q3 Week 12 Case study 3 Points Complete the Week 12 Case Study. After creating a plot of your data, export the plot as a PDF and upload it here. Determine which group had a higher center and which had a higher IQR based on the plot. Higher center? Higher IQR? Plot of data: Please select file(s) Select file(s) Save Answer 1990s songs! 2000s songs! 1990s songs! 2000s songs! " 4/6/21, 1(22 AMSubmit Assignment 11 | Gradescope Page 12 of 13https://www.gradescope.com/courses/224306/assignments/1138477/submissions/new Q4 Cite your sources 1 Point On each assignment, you will be asked who you worked with and what resources you used. a) Please list all resources you used. You do not need to use formal reference formats (e.g., APA/MLA), but if you used any websites or textbooks, please include the title and URL. You must include the course textbook here to earn credit. Include RStudio anytime you use that as well. b) Please list the first and last name of any people you worked with on this assignment. If you use the Math Learning Center, you can simply state MLC. If you did not work with anyone or use