It is hypothesized that there are fluctuations in norepinephrine (NE) levels which accompany fluctuations in affect with bipolar affective disorder (manic-depressive illness). Thus, during depressive states, NE levels drop; during manic states, NE levels increase. To test this relationship, researchers measured the level of NE by measuring the metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG in micro gram per 24 hour) in the patient's urine experiencing varying levels of mania/depression. Increased levels of MHPG are correlated with increased metabolism (thus higher levels) of central nervous system NE. Levels of mania/depression were also recorded on a scale with a low score indicating increased mania and a high score increased depression. The data is provided below. MHPG     Affect 980           22 1209         26 1403         8 1950         10 1814          5 1280          19 1073          26 1066          12 880            23 776            28 a. Can MHPG significantly predict affect? Please support your answer. b. Please report the regression equation and then interpret the following: i. Slope – ii. Intercept – iii. R (squared)   c. Increases in MHPG cause increases in affect...true or false? Please explain.

A researcher conducts a two-year study comparing the number of cavities in a group of 30 randomly selected young children from the community before and after the application of fluoride to test if there is a decrease in the number of cavities. This is an example of a/an: Independent-samples t test   or    Dependent-samples t test?

A group of 10-year-old boys were first ascertained in a camp for diabetic boys. They had their weight measured at baseline and again when they returned to camp 1 year later. Each time, a serum sample was obtained from which a determination of hemoglobin A1c (HgbA1c) was made. HgbA1c (also called glycosylated hemoglobin) is routinely used to monitor compliance with taking insulin injections. Usually, the poorer the compliance, the higher the HgbA1c level will be. The hypothesis is that the level HgbA1c is related to weight. The data in Table 11.28 were obtained. 11.95 Compute a rank correlation between change in weight and change in HgbA1c, each over 1 year. Use this measure to directly test the hypothesis that change in weight over 1 year is related to change in HgbA1c. Report a two-tailed p-value, and provide a 95% confidence interval for the underlying rank correlation.

A sample of 25 individuals was taken to investigate the relationship between their annual income and number of years of education. The Pearson's correlation coefficient (r) was calculated to be 0.6. Test the hypothesis at a significance level of 0.01 that the population correlation coefficient is different from 0.

A researcher conducts a between-subjects study to determine whether low levels of the neurochemical serotonin leads to an increase in aggression. One sample of rats serves as a control group and receives a placebo that does not affect normal levels of serotonin. A second sample of rats receives a drug that lowers brain levels of serotonin. Using an alpha level of a = .05, the researcher then tests the animals by recording the number of aggressive responses each of the rats display. The data are as follows: a.) Step 1: State the Hypotheses Ho: H₁: Control n = 10 M = 14 SS=180.5 b.) Step 2: Determine the critical region and draw it on the distribution above: df = > *critical SM₁-M₂ Low Serotonin n = 15 M = 19 SS = 130.0 c.) Step 3: Calculate the test statistic using the provided sample data: tobs d.) Step 4: Make a decision. Circle one: Reject Null (Ho) or Fail to Reject Null (Ho) e.) State your conclusions about the research scenario in sentence form: d= f.) What is the estimated effect…

Inorganic phosphorous is a naturally occurring element in all plants and animals, with concentrations increasing progressively up the food chain (fruit < vegetables < cereals < nuts < corpse). Geochemical surveys take soil samples to determine phosphorous content (in ppm, parts per million). A high phosphorous content may or may not indicate an ancient burial site, food storage site, or even a garbage dump. Independent random samples from two regions gave the following phosphorous measurements (in ppm). Assume the distribution of phosphorous is mound-shaped and symmetric for these two regions. REGION I:X1;N1=15 857 1,551 1,230 875 1,080 2,330 1,850 1,860 2,340 1,080 910 1,130 1,450 1,260 1,010 REGION II:X2;N2=14 538 812 790 1,230 1,770 960 1,650 860 890 640 1,180 1,160 1,050 1,020 (a) Use a calculator with mean and standard deviation keys to verify that x1, s1, x2, and s2. (Round your answers to four decimal places.) x1= ppm s1= ppm x2= ppm s2= ppm…

700 doctors went through extra training compared to 1200 doctors who did not. Of the doctors who went through extra training, 125 of them majored in psychology. Of the 1200 doctors who did not do extra training, 174 of them majored in psychology.  Perform a hypothesis test to see if there is a statistically significant evidence that the proportion of doctors who went through extra training is significantly greater than the proportion of doctors who did not.  Perform the test at the alpha = .5 level. What is the p value and conclusion of this test?

Reggie is running his stats for a project he just finished.  He had participants came in to the lab and gave them a drug treatment (either a control or an experimental compound) at different times during the day (morning, afternoon, and night).  Each participant went through all off of the conditions.  He ran an ANOVA and tested for the main effects and their interaction.  Assuming that only the main effects (and not the interaction) came back significant, interpret his results (no need to include tests statistics).

A randomized trial assessed the efficacy of colchicine (an anti-inflammatory drug) in reducing recurrence of pericarditis (inflammation of the outer layer of the heart). The study randomized 42 patients to colchicine and 49 patients to standard therapy, and followed them all for 6 months. They reported the following results: Colchicine Standard Rx 0-15% 35-50% 60-75% Developed Recurrent Pericarditis Yes No 10 32 27 In what range is the relative risk reduction? 85-100% 22 32 59 42 49 91 The relative risk reduction can not be calculated from these data