Example#1:A researcher wishes to examine whether time of day (morning versus afternoon) affects the memory of older and younger participants. He obtains a sample of 40 older individuals and 40 younger individuals and gives them a passage to read. They are later given a test over the passage (scores on the test could range from O to 30). HaJf of the individuals are randomly assigned to read the passage and take the test in the morning, and the other half do so in the afternoon. The data are reported in the table below (the numbers represent mean test scores for each group3; that is, "M" is mean). Morning Testing Afternoon Testing M=8 Older Adults M= 15 Younger Adults М- 16 М-20

Researchers wish to study the effect of daily brain teasers on a person's intelligence. The researchers randomly choose 20 students from their local college campus. Day one of the test, every student is given an IQ test. The students are then randomly divided into Group A and Group B (10 students each). Group A is given daily brain teasers, while Group B were not instructed to participate in anything outside their normal routine. At the end of a 30 day period, each member of the group takes an IQ test. The students are aware of what group they are in, but the researchers have no idea until the results are given. The test given to Group A would be considered the Control Treatment Variable Placebo

A researcher is comparing the effectiveness of three devices designed to help people who snore. There are 210 people who snore participating in the experiment. Using a table of random digits starting from the first row and column, the researcher will randomly place the participants into three equally sized treatment groups suitable for comparison. Which number range would be needed to label the subjects correctly? O 0-2 O 1-3 O 000-210 O 001-210

As part of a statistics project, a teacher brings a bag of marbles containing 700 white marbles and 300 red marbles. She asks her students to determine how many red marbles are in the bag without counting them.A student randomly draws 100 marbles from the bag. Of the 100 marbles, 33 are red.The target population consists of The 100 marbles drawn by the student The 1000 marbles in the bag None of the above The 33 red marbles drawn by the student The 300 red marbles in the bag The sample consists of The 1000 marbles in the bag The 100 marbles drawn by the student The 33 red marbles drawn by the student None of the above The 300 red marbles in the bag Based on the sample, the student would estimate that ------   marbles in the bag were red.

A crossover trial is a type of experiment used to compare two drugs. Subjects take one drug for a period of time, then switch to the other. The responses of the subjects are then compared using matched-pair methods. In an experiment to compare two pain relievers, seven subjects took one pain reliever for two weeks, then switched to the other. They rated their pain level from 1 to 10, with larger numbers representing higher levels of pain. The results were: Subject Drug A Drug B 1 6 5 2 3 1 3 4 4 7 6 2 7 4 2 Can you conclude that the mean pain level is less with drug B? Use a=0.05. (1) Critical Value (Round off to 3 decimal places): (2) Test Statistic (Round off to 2 decimal places): (3) Conclusion: (Type 'Reject HO' or 'Fail to Reject HO')

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 (…

Mr Alsup asked the studentS in his third-and sixth-period English classes whether they had chosen a topic for thier writing assignment. he recorded the data in a two-way table, as shown below English class   Yes  No  Total Third period 24 6 30 Sixth period  22 3 25 Total 46 9 55   if jannette in in mr alsup sixth-period english class what is the probablity that she has not chosen a topic for her writing assignment? a- 3% b- 5% c- 12% d-14%