Suppose a researcher is interested in the effect of a new treatment drug at increasing CD4 count in patients with HIV. In this study, each patient treated with the study drug is frequency paired with another patient on a number of characteristics treated with a placebo to insure independence among samples. Assume the following sample of participants enrolled in the study represents an appropriate approximation to the normal distribution. A 347 A’ 326 B 346 B’ 321 C 338 C’ 314 D 334 D’ 316 E 342 E’ 30 B) Carry out a paired-sample t test to investigate the effectiveness at increasing CD4 count in immunocompromised patients. Write out the null and alternative hypotheses using an α=0.05, and correctly interpret your results.

The accompanying data were read from a plot (and are a subset of the complete data set) given in an article. The data represent the mean response times for a group of individuals with closed-head injury (CHI) and a matched control group without head injury on 10 different tasks. Each observation was based on a different study, and used different subjects, so it is reasonable to assume that the observations are independent. Study 1 y= 2 3 4 5 6 7 8 9 10 Mean Response Time CHI Control 250 360 475 525 610 740 880 920 1010 1200 304 492 432 659 683 922 1044 1421 1329 1481 1815 (a) Fit a linear regression model that would allow you to predict the mean response time for those suffering a closed-head injury from the mean response time on the same task for individuals with no head injury. (Round your answers to four decimal places.) (b) Do the sample data support the hypothesis that there is a useful linear relationship between the mean response time for individuals with no head injury and the…

An ANOVA is used to compare the mean GPA of the following groups of students.

All of the following are descriptive statistics EXCEPT a. independent samples t-testb. medianc. variance d. frequency tables

The accompanying data were read from a plot (and are a subset of the complete data set) given in an article. The data represent the mean response times for a group of individuals with closed-head injury (CHI) and a matched control group without head injury on 10 different tasks. Each observation was based on a different study, and used different subjects, so it is reasonable to assume that the observations are independent. y = Study 1 2 3 4 5 6 7 8 9 10 Mean Response Time CHI 302 492 658 684 922 1044 1421 1329 1481 1815 t = Control 250 360 475 (a) Fit a linear regression model that would allow you to predict the mean response time for those suffering a closed-head injury from the mean response time on the same task for individuals with no head injury. (Round your answers to four decimal places.) 525 610 740 880 920 1010 1200 (b) Do the sample data support the hypothesis that there is a useful linear relationship between the mean response time for individuals with no head injury and the…

. ​If one sample has n = 5 scores with SS = 40 and a second sample has n = 5 scores with SS = 20, then what is the pooled variance

An immunologist wants to compare two rabies vaccines. People who had previously received the vaccine were divided into two groups. The first group received a booster dose of type I vaccine and the second group received a booster dose of type II vaccine. Two weeks later the antibody level was measured. The average number of antibodies in each group appears in the following table: Do these data indicate that there is a difference in the effectiveness of the two vaccines used for booster doses? Assume a normal distribution and equal population variances. What type of hypothesis test will allow us to reach a conclusion in the situation posed above? A. Variance test B. Unilateral for difference in proportions C. Bilateral for average difference D. Unilateral for change in effectiveness

. What are the values of SS and variance s? for the following sample of n=3 scores? Sample: 1, 4, 7

The popularity of computer, video, online, and virtual reality games has raised concerns that they might negatively affect youth. The data in this exercise are based on a recent survey of 14- to 18-year-olds in Connecticut high schools. The table displays the grade distributions of boys who have and have not played video games. Played games Never played games A's and B's: C's: A's and B's D's and F's: 744 210 Grade Average C's 445 140 D's and F's Find the conditional distribution of grades (the response variable) for nonplayers. Give your answers to two decimal places. 197 84 % % %

The National Football League (NFL) records a variety of performance data for individuals and teams. To investigate the importance of passing on the percentage of games won by a team, the following data show the average number of passing yards per attempt (Yds/Att) and the percentage of games won (WinPct) for a random sample of 10 NFL teams for the 2011 season (NFL website). Team Yds/Att WinPct 5.7 26 Arizona Cardinals Atlanta Falcons Carolina Panthers 7.6 67 7.3 52 6.9 51 Chicago Bears Dallas Cowboys 5.1 17 8.6 82 New England Patriots Philadelphia Eagles Seattle Seahawks 5.3 21 6.6 41 St. Louis Rams 6.5 41 Tampa Bay Buccaneers. 6.1 38 a. Choose the correct a scatter diagram with the number of passing yards per attempt on the horizontal axis and the percentage of games won on the vertical axis. B. A. WinPct WinPct 80 DD J F1 70- 60- 50+ -40- 30 20- F2 80 F3 000 000 F4 F5 80- -70 60- 50- 40- 30- 20- S F6 ● - F7 DII F8 F9 F10 () F11 <))) F12 A