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Inference about Variables: Part III Review

Inference about Variables: Part III Review. BPS chapter 22. © 2006 W.H. Freeman and Company. Inference methods.

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Inference about Variables: Part III Review

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  1. Inference about Variables: Part III Review BPS chapter 22 © 2006 W.H. Freeman and Company

  2. Inference methods Many people believe that playing chess can have a positive effect on reading ability. To investigate this belief, researchers took a random sample of 53 student chess players and enrolled them in an after-school chess instruction program. To gauge their reading ability, each chess player took the Degree of Reading Power Test before and after completing the program. To see whether the average change in DRP test score is positive, which type of inference procedure should the researchers use? • One-sample t for a mean • Two-sample t for means • Matched pairs t for a mean • One-sample z for proportion • Two-sample z for proportions

  3. Inference methods (answer) Many people believe that playing chess can have a positive effect on reading ability. To investigate this belief, researchers took a random sample of 53 student chess players and enrolled them in an after-school chess instruction program. To gauge their reading ability, each chess player took the Degree of Reading Power Test before and after completing the program. To see whether the average change in DRP test score is positive, which type of inference procedure should the researchers use? • One-sample t for a mean • Two-sample t for means • Matched pairs t for a mean • One-sample z for proportion • Two-sample z for proportions

  4. Inference methods Many people believe that playing chess can have a positive effect on reading ability. To investigate this belief, researchers took a random sample of 53 student chess players and enrolled them in an after-school chess instruction program. To gauge their reading ability, each chess player took the Degree of Reading Power Test before and after completing the program. To see whether the average change in DRP test score is positive, should the researchers use a confidence interval or a hypothesis test? • Confidence interval • Hypothesis test

  5. Inference methods (answer) Many people believe that playing chess can have a positive effect on reading ability. To investigate this belief, researchers took a random sample of 53 student chess players and enrolled them in an after-school chess instruction program. To gauge their reading ability, each chess player took the Degree of Reading Power Test before and after completing the program. To see whether the average change in DRP test score is positive, should the researchers use a confidence interval or a hypothesis test? • Confidence interval • Hypothesis test

  6. Inference methods A study at Johns Hopkins investigated whether maintaining surgery patients’ body temperatures close to normal by heating the patients during surgery is associated with fewer event of morbid heart attack. Surgery patients included in the study were randomly assigned to one of two treatment groups. In the normalthermic group, patients’ core temperatures were maintained near normal 36.5 degrees Celsius. In the hypothermic group, patients’ core temperatures were allowed to decrease to about 34.5 degrees Celsius. To determine whether the proportion of morbid heart attacks is less for the normalthermic group, which type of inference procedure should the researchers use? • One-sample t for a mean • Two-sample t for means • Matched pairs t for a mean • One-sample z for proportion • Two-sample z for proportions

  7. Inference methods (answer) A study at Johns Hopkins investigated whether maintaining surgery patients’ body temperatures close to normal by heating the patients during surgery is associated with fewer event of morbid heart attack. Surgery patients included in the study were randomly assigned to one of two treatment groups. In the normalthermic group, patients’ core temperatures were maintained near normal 36.5 degrees Celsius. In the hypothermic group, patients’ core temperatures were allowed to decrease to about 34.5 degrees Celsius. To determine whether the proportion of morbid heart attacks is less for the normalthermic group, which type of inference procedure should the researchers use? • One-sample t for a mean • Two-sample t for means • Matched pairs t for a mean • One-sample z for proportion • Two-sample z for proportions

  8. Inference methods A study at Johns Hopkins investigated whether maintaining surgery patients’ body temperatures close to normal by heating the patients during surgery is associated with fewer event of morbid heart attack. Surgery patients included in the study were randomly assigned to one of two treatment groups. In the normalthermic group, patients’ core temperatures were maintained near normal 36.5 degrees Celsius. In the hypothermic group, patients’ core temperatures were allowed to decrease to about 34.5 degrees Celsius. To determine whether the proportion of morbid heart attacks is less for the normalthermic group, should the researchers use a confidence interval or a hypothesis test? • Confidence interval • Hypothesis test

  9. Inference methods (answer) A study at Johns Hopkins investigated whether maintaining surgery patients’ body temperatures close to normal by heating the patients during surgery is associated with fewer event of morbid heart attack. Surgery patients included in the study were randomly assigned to one of two treatment groups. In the normalthermic group, patients’ core temperatures were maintained near normal 36.5 degrees Celsius. In the hypothermic group, patients’ core temperatures were allowed to decrease to about 34.5 degrees Celsius. To determine whether the proportion of morbid heart attacks is less for the normalthermic group, should the researchers use a confidence interval or a hypothesis test? • Confidence interval • Hypothesis test

  10. Inference methods Researchers at an oil refinery northeast of San Francisco measured carbon monoxide levels in emissions from one of their stacks on 31 separate days. Assume that these 31 measurements can be considered a random sample of daily carbon monoxide emissions levels. If the researchers want to estimate the mean carbon monoxide emission level from this stack, which type of inference procedure should they use? • One-sample t for a mean • Two-sample t for means • Matched pairs t for a mean • One-sample z for proportion • Two-sample z for proportions

  11. Inference methods (answer) Researchers at an oil refinery northeast of San Francisco measured carbon monoxide levels in emissions from one of their stacks on 31 separate days. Assume that these 31 measurements can be considered a random sample of daily carbon monoxide emissions levels. If the researchers want to estimate the mean carbon monoxide emission level from this stack, which type of inference procedure should they use? • One-sample t for a mean • Two-sample t for means • Matched pairs t for a mean • One-sample z for proportion • Two-sample z for proportions

  12. Inference methods Researchers at an oil refinery northeast of San Francisco measured carbon monoxide levels in emissions from one of their stacks on 31 separate days. Assume that these 31 measurements can be considered a random sample of daily carbon monoxide emissions levels. If the researchers want to estimate the mean carbon monoxide emission level from this stack, should the researchers use a confidence interval or a hypothesis test? • Confidence interval • Hypothesis test

  13. Inference methods (answer) Researchers at an oil refinery northeast of San Francisco measured carbon monoxide levels in emissions from one of their stacks on 31 separate days. Assume that these 31 measurements can be considered a random sample of daily carbon monoxide emissions levels. If the researchers want to estimate the mean carbon monoxide emission level from this stack, should the researchers use a confidence interval or a hypothesis test? • Confidence interval • Hypothesis test

  14. Inference methods An experiment was conducted to see if elderly patients had more trouble keeping their balance when loud, unpredictable noises were made compared to younger patients who were also exposed to the noises. To see whether the mean amount of sway differs significantly between the elderly and younger patients, which type of inference procedure should the researchers use? • One-sample t for a mean • Two-sample t for means • Matched pairs t for a mean • One-sample z for proportion • Two-sample z for proportions

  15. Inference methods (answer) An experiment was conducted to see if elderly patients had more trouble keeping their balance when loud, unpredictable noises were made compared to younger patients who were also exposed to the noises. To see whether the mean amount of sway differs significantly between the elderly and younger patients, which type of inference procedure should the researchers use? • One-sample t for a mean • Two-sample t for means • Matched pairs t for a mean • One-sample z for proportion • Two-sample z for proportions

  16. Inference methods An experiment was conducted to see if elderly patients had more trouble keeping their balance when loud, unpredictable noises were made compared to younger patients who were also exposed to the noises. To see whether the mean amount of sway differs significantly between the elderly and younger patients, should the researchers use a confidence interval or a hypothesis test? • Confidence interval • Hypothesis test

  17. Inference methods (answer) An experiment was conducted to see if elderly patients had more trouble keeping their balance when loud, unpredictable noises were made compared to younger patients who were also exposed to the noises. To see whether the mean amount of sway differs significantly between the elderly and younger patients, should the researchers use a confidence interval or a hypothesis test? • Confidence interval • Hypothesis test

  18. Inference methods If researchers want to estimate the proportion of drivers that speed (drive faster than 65 miles per hour) on a stretch of interstate west of Hagerstown, Maryland, which type of inference procedure should they use? • One-sample t for a mean • Two-sample t for means • Matched pairs t for a mean • One-sample z for proportion • Two-sample z for proportions

  19. Inference methods (answer) If researchers want to estimate the proportion of drivers that speed (drive faster than 65 miles per hour) on a stretch of interstate west of Hagerstown, Maryland, which type of inference procedure should they use? • One-sample t for a mean • Two-sample t for means • Matched pairs t for a mean • One-sample z for proportion • Two-sample z for proportions

  20. Inference methods If researchers want to estimate the proportion of drivers that speed (drive faster than 65 miles per hour) on a stretch of interstate west of Hagerstown, Maryland, should the researchers use a confidence interval or a hypothesis test? • Confidence interval • Hypothesis test

  21. Inference methods (answer) If researchers want to estimate the proportion of drivers that speed (drive faster than 65 miles per hour) on a stretch of interstate west of Hagerstown, Maryland, should the researchers use a confidence interval or a hypothesis test? • Confidence interval • Hypothesis test

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