find the null and alternative hypotheses and what kind of test it is B. Find the P-value C. Determine whether to reject H0  D. Conclusion

In a large scale study of energy conservation in single family homes, 20 homes were randomly selected from homes built in a housing development in southern England. Ten of the houses, randomly selected from the 20 houses selected for the study, were constructed with standard levels of insulation (70 mm of roof insulation and 50 mm of insulation in the walls). The other 10 houses were constructed with extra insulation (120 mm of roof insulation and 100 mm of insulation in the walls). Each house was heated with a gas furnace and energy consumption was monitored for eight years. The data shown below give annual gas consumption in MWh for each of the 20 houses. Standard Insulation Extra Insulation 13.8 15.1 17.8 13.9 18.0 15.9 17.3 17.2 16.9 15.2 19.9 13.8 13.6 11.3 17.6 13.2 15.9 18.8 12.3 14.0 Sample means Sample Standard Deviation 16.31 14.84 2.38 2.12

A state fisheries commission wants to estimate the number of bass caught in a given lake during a season in order to restock the lake with the appropriate number of young fish. The commission could get a fairly accurate assessment of the seasonal catch by extensive “netting sweeps" of the lake before and after a season, but this technique is much too expensive to be done routinely. Therefore, the commission samples a number of lakes and record the seasonal catch (thousands of bass per square mile of lake area) and size of lake (square miles). A simple linear regression was performed and the following R output obtained. Estimate Std. Error t value Pr(>|t|) (Intercept) 2.5463 0.4427 5.7513 0.0000 size 0.0667 0.3672 0.1818 0.8578 If a scatterplot showed a non-linear relationship between the response and explanatory variables, what should be done? O Nothing. Continue the analysis as is. Stop the analysis. Perform a natural log transformation on the response variable first. O Perform a…

Dr. Mackintosh believes a new olfactory therapy would be more successful in promoting weight loss among obese patients. His patients are first weighed and then randomly assigned to olfactory therapy, dance therapy, or a control condition. At the end of the three weeks, the amount of weight lost is recorded. The results indicate no significant difference in the amount of weight lost between the three conditions. If true differences existed between the conditions, but they were not detected, what kind of error occurred?

A researcher is interested in the effect of the pandemic on social media use among college students. The researcher hypothesizes that college students spend more time on social media thanthey did before the pandemic. To test his hypothesis, he randomly selected 50 college students and asked how many hours do they spend on social media per day before and after the pandemic. a)  What is the research question? b)  What is/are the variable(s)? What graphs can be used to display the variable(s) visually? c)  What statistical test can be used to answer the research question?

Is injecting medical cement effective in reducing pain for people who have suffered fractured vertebrae? A paper describes an experiment to compare patients who underwent vertebroplasty (the injection of cement) to patients in a placebo group who underwent a fake procedure in which no cement was actually injected. Because the placebo procedure was similar to the vertebroplasty procedure except for the actual injection of cement, patients participating in the experiment were not aware of which treatment they received. All patients were asked to rate their pain at three different times—3 days, 14 days, and 1 month after the procedure. Summary statistics are given in the accompanying table.   Pain Intensity   Vertebroplasty Group Placebo Group   n = 76 n = 62   mean sd mean sd 3 days 4.2 2.8 3.9 2.9 14 days 4.3 2.9 4.5 2.8 1 month 3.9 2.9 4.6 3.0   Construct and interpret a 95% confidence interval for the difference in mean pain intensity 3 days after treatment for the…

A study was conducted to determine whether big-city and small-town dwellers differed in their helpfulness to strangers. In this study, the investigators rang the doorbells of strangers living in a large City or small towns in the vicinity. They explained they had misplaced the address of a friend living in the neighbourhood and asked to use the phone. The following data show the number of individuals who admitted or did not admit the strangers (the investigators) into their homes: Helpfulness to strangers   Admitted strangers into their home  Didnot admit strangers into their home  Big city dwellers 60 90 Small town dwellers 70 30 State the dependent and independent variable  Is this a directional or non directional

Angioplasty is a medical procedure in which an obstructed blood vessel is widened. In some cases, a wire mesh tube, called a stent, is placed in the vessel to help it remain open. A study was conducted to compare the effectiveness of a bare metal stent with one that has been coated with a drug designed to prevent reblocking of the vessel. A total of 5329 patients received bare metal stents, and of these, 830 needed treatment for reblocking within a year. A total of 1125 received drug-coated stents, and 146 of them required treatment within a year. Can you conclude that the proportion of patients who needed retreatment differs between those who received bare metal stents and those who received drug-coated stents? Let p1 denote the proportion of patients with bare metal stents who needed retreatment and p2 denote the proportion of patients with drug-coated stents who needed retreatment. Use the α=0.10 level of significance and the P-value method with the TI-84 Plus calculator. a)State…

Independent studies show that 26 out of 40 r/s full-time students favor a shorter semester system, while 38 out of 50 r/s part-time students favor the same. Construct a 98% c.i. for the difference between the overall percentage of full-time students favoring a shorter semester system and that of part-time students.

A researcher took a random sample of 200 new mothers in the United States (Group 1) and found that 16% of them experienced some form of postpartum depression. Another random sample of 200 new mothers in France (Group 2), where mothers receive 16 weeks of paid maternity leave, found that 11% experienced some form of postpartum depression. Can it be concluded that the percent of women in the United States experience more postpartum depression than the percent of women in France? Use α=0.05. Select the correct alternative hypothesis and decision