A coach uses a new technique to train gymnasts. 7 gymnasts were randomly selected and their competition scores were recorded before and after the training. The results are shown below.   Subject A B C D E F G Before 9.5 9.4 9.6 9.5 9.5 9.6 9.7 After 9.6 9.6 9.6 9.4 9.6 9.9 9.5 Using a 0.01 level of significance, test the claim that the training technique is effective in raising the gymnasts' scores. (Before-After)    Complete the following analysis. 1. This is a left -tailed test. 2. The test statistic is equal to t= [ Select ] -0.21 -3.12 -0.88 1.93 . 3. If the value of the test statistic is less than [ Select ] -1.645 -3.14 -1.58 -1.96 then you will reject the null hypothesis.  4. If the P-value is less than [ Select ] .05 .005 .1 .01 , then you will reject the null hypothesis. 5. The P-value is equal to 0.21 .  6. Fail to reject the null hypothesis. 7. At the 1% significance level, there [ Select ] is not is evidence to support the claim that the technique is effective in raising the gymnasts' scores.   (You should technically be checking graphs to make sure that certain assumptions are met. Of course, this data doesn't meet these conditions, so in real life you wouldn't do this analysis. You would need another method than what I have given you. However, we are just going to check that we can do the computations, even if they are meaningless in this case.)          多重下拉选择题

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Your friend works at a city council which is having issues with feral pigeons Links to an external site. . The city's councillors looked into the use of peregrine falcons Links to an external site. to control pigeon numbers, and a one-month trial was proposed (at great cost to the ratepayer).  The one-hour count of pigeons at 8 sites across the city was recorded prior to the release of the falcons as a trial. A month later, the same one-hour count of pigeons was repeated at the same 8 sites across the city. The counts are as below: bef <- c(74, 68, 73, 71, 72, 82, 74, 71, 65) aft <- c(58, 49, 86, 52, 60, 38, 44, 67, 76) The city wants to know whether the use of falcons have made a significant difference to pigeon numbers. They've tasked your friend to determine whether there's a difference. Unfortunately, he has no understanding of statistics so he asked ChatGPT for advice on how to proceed. Using the advice from ChatGPT, he decided to perform a t-test and is about to give the following output and the conclusion to the city council.  Welch Two Sample t-test data: bef and aft t = 2.484, df = 9.4667, p-value = 0.03355 alternative hypothesis: true difference in means is not equal to 0 95 percent confidence interval: 1.281491 25.385176 sample estimates: mean of x mean of y 72.22222 58.88889 Conclusion: "Yes, absolutely! When the p-value is less than your chosen significance level (commonly 0.05), it indicates that there is sufficient evidence to reject the null hypothesis. In your case, with a p-value of 0.03355, you can indeed conclude that there is a statistically significant difference between the two sets of data (bef and aft)." Was your friend correct? Select all statements that apply. 

A city created a new advertising campaign for 7 of its attractions and wanted to assess whether the campaign has affected the number of tourists visiting its attractions by comparing the number of visitors at each site before and after the campaign.  A paired t-test was performed and the output was as follows. Paired t-test data: before and after t = -3.6034, df = 6, p-value = 0.01132 alternative hypothesis: true mean difference is not equal to 0 95 percent confidence interval: -15.111451 -2.888549 sample estimates: mean difference -9 Which is the most appropriate conclusion to draw at α = 0.01?

A medical researcher uses pre and post test averages of counts of red blood cells on 2319 patients to determine the efficacy of a new drug in increasing average red blood cell counts. What test should be used to determine if the drug is successful?

A coach uses a new technique to train gymnasts. 7 gymnasts were randomly selected and their competition scores were recorded before and after the training. The results are shown below.   Subject A B C D E F G Before 9.5 9.4 9.6 9.5 9.5 9.6 9.7 After 9.6 9.6 9.6 9.4 9.6 9.9 9.5 Using a 0.01 level of significance, test the claim that the training technique is effective in raising the gymnasts' scores. (Before-After)    Complete the following analysis. 1. This is a [ Select ] right two left -tailed test. 2. The test statistic is equal to t= [ Select ] -0.88 1.93 -3.12 -0.21 . 3. If the value of the test statistic is less than [ Select ] -3.14 -1.96 -1.645 -1.58 then you will reject the null hypothesis.  4. If the P-value is less than [ Select ] .1 .01 .05 .005 , then you will reject the null hypothesis. 5. The P-value is equal to 0.21 .  6. [ Select ] Fail to reject Reject the null hypothesis. 7. At the 1% significance level, there is not evidence to support the claim that the technique is effective in raising the gymnasts' scores.   (You should technically be checking graphs to make sure that certain assumptions are met. Of course, this data doesn't meet these conditions, so in real life you wouldn't do this analysis. You would need another method than what I have given you. However, we are just going to check that we can do the computations, even if they are meaningless in this case.)          

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