A school psychologist is interested in determining if children with attention deficit hyperactivity disorder (ADHD) learn better if English literature is read to them rather than having them read the material alone by themselves. A random sample of 10 sixth graders with ADHD is selected and divided into two groups of n=9. One of the groups has a story read to them (Listening Group) and the other reads the story alone by themselves (Reading Group). A test on the story is given after each group has finished reading or hearing the story. The following scores were obtained with 20 being a perfect score. What is the t-statistic?

would this be a one tail or two tail test?

In a study about learning styles, researchers used a group of 64 elementary school students who volunteered to be part of the study. The researchers gave each student a pre-test and based upon the results, they divided them into 32 pairs of similarly scoring students. School administrators then randomly assigned one student from each pair to mathematics instruction online while the other student received in-person instruction in a traditional classroom. At the end of the year, all 64 students received a mathematics assessment, measured on a 100-point scale.   The researchers calculated the difference (in person −− online) in the mathematics assessment scores for each pair of students. The 32 differences had a mean of 15 and a standard deviation of 3.9 points.   Construct and interpret a 95% confidence interval for the mean difference (in person −− online) in the mathematics assessment scores for all pairs of students like these who learn math either face-to-face or online.

A tv report conducted a survey of 681 people in Washington state and found that 26% of the population believe that Mt Saint Helen's will have a repeat eruption this year.  In the accompanying dialogue, the reporter states,  we are 91% confident that the true proportion of people in Washington state who believe that Mt saint Helen's wil have a repeat eruption this year lies between 20% and 32%. What does 91% represent in the report?

A high school track coach wanted to test whether giving the students an energy drink could affect performance during the 100 meter race. The coach split the 26 boys into two equal sized groups, where Group 1 was given the energy drink and Group 2 was not. The 100 meter race times were recorded during practice and shown in the table below. What inference can be made about the results? Group 1 Group 2 12.2 13 12.5 12.3 13.3 12.8 12.9 13 13 13.8 12.1 13 13 13 13 13 12.1 13 13 13 12.1 13 12.8 13 13 12.6     Mean: 12.7 Mean: 13   Since the simulation shows ( many cases or free cases )?  where a mean  difference of ( solve for this answer )   or less occurred when the groups were re-randomized, it can be inferred that the mean difference observed in the study was ( very possibly or very unlikely )  ?due to the random assignment of participants into groups, so the results of the study are (…

Maddie conducts a study to see if listening to music helps students learn math.  She surveys a random sample of 250 college sophomores who completed a math class within the past six months.  She asks them to indicate how frequently they listened to music while studying math.  The students also report their final grade in the math class at the end of the semester.   Select the statement below that is false.     There is no placebo in this study.     Maddie conducted an observational study.     A confounding variable could be how often the participants studied math.     The population Maddie studied was 250 college sophomores.

Craik & Tulving ran an experiment to determine how depth of processing during study affects memory. In the study phase, 12 participants made judgments about words. In one block of trials (the visual condition) they indicated whether the words were written in upper case or lower case; in another block of trials (the auditory condition) they indicated whether the words contained an "ee" sound; in another block of trials (the meaning condition) they indicated whether the meaning of the words was pleasant or unpleasant. There were 12 words in each block. After completing the study phase, participants were asked to write down all the words they could remember. Here are the data: Mean Visual 3.5 Auditory 4.5 Meaning 6.0 Standard Deviation 1.5 1.6 1.9 Compared to the within-subjects design, the between-subjects design (select all that apply) Oa. Would have less statistical power O b. Would be less prone to experimenter bias O c. Would be less prone to order effects Od. Would have better…

A doctor wanted to study the effect of four different treatments on mental health. A group of 100 adults experiencing depression volunteered for the study. The doctor randomly assigned one-fourth of them to each of four groups. Group 1 followed a specific exercise plan, group 2 followed a specific diet plan, group 3 followed an exercise and diet plan, and group 4 did not follow any plan. After 4 weeks, the doctor contacted each participant and asked them if they felt any better. The results are displayed in the table.    The doctor would like to know if these data provide convincing evidence that the distribution of responses differs across the treatment groups in the population of all patients like these. The random condition is met. The 10% condition is not needed because random sampling did not take place. This table of expected counts shows that all expected counts are at least 5.   What is the value of the chi-square test statistic? χ‑2 = 5.03 χ‑2 = 6.26 χ‑2 = 25.33 χ‑2 = 39.22