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A pharmaceutical company wants to test the effectiveness of an experimental drug meant to reduce high cholesterol. The researcher at the pharmaceutical company has decided to test the effectiveness of the drug through a completely randomized design. She has obtained 20 volunteers with high cholesterol: Ann, John, Michael, Kevin, Marissa, Christina, Eddie, Shannon, Julia, Randy, Sue, Tom, Wanda, Roger, Laurie, Rick, Kim, Joe, Colleen, and Bill. Number the volunteers from 1 to \(20 .\) Use a random-number generator to randomly assign 10 of the volunteers to the experimental group. The remaining volunteers will go into the control group. List the individuals in each group.

Short Answer

Expert verified
Experimental Group: John, Marissa, Eddie, Shannon, Randy, Tom, Roger, Rick, Joe, Bill. Control Group: Ann, Michael, Kevin, Christina, Julia, Sue, Wanda, Laurie, Kim, Colleen.

Step by step solution

01

- Number the Volunteers

Assign a unique number from 1 to 20 to each volunteer. For example: Ann (1), John (2), Michael (3), Kevin (4), Marissa (5), Christina (6), Eddie (7), Shannon (8), Julia (9), Randy (10), Sue (11), Tom (12), Wanda (13), Roger (14), Laurie (15), Rick (16), Kim (17), Joe (18), Colleen (19), and Bill (20).
02

- Use a Random-Number Generator

Use a random-number generator to select 10 unique numbers between 1 and 20. These numbers will correspond to the volunteers assigned to the experimental group.
03

- Assign Volunteers to Experimental Group

Match the selected random numbers to the volunteers' assigned numbers to determine who falls into the experimental group. For instance, if the random numbers are 2, 5, 7, 8, 10, 12, 14, 16, 18, and 20, then the experimental group includes John (2), Marissa (5), Eddie (7), Shannon (8), Randy (10), Tom (12), Roger (14), Rick (16), Joe (18), and Bill (20).
04

- Assign Remaining Volunteers to Control Group

The volunteers not selected in Step 3 will be assigned to the control group. Using the previous example, the control group includes Ann (1), Michael (3), Kevin (4), Christina (6), Julia (9), Sue (11), Wanda (13), Laurie (15), Kim (17), and Colleen (19).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

randomized control trial
A randomized control trial (RCT) is a powerful technique used in scientific research to test the effectiveness of treatments.
This method ensures that the results are reliable and free from bias.
In an RCT, participants are randomly assigned to either the experimental group or the control group.
The experimental group receives the treatment, while the control group does not, often getting a placebo instead.
By comparing outcomes between these groups, researchers can determine if the treatment has any effect.
Randomization removes biases, as neither the researchers nor the volunteers control who gets the treatment.
random number generator
A random number generator is a tool that produces numbers in a random sequence.
It’s a critical component in randomized control trials to ensure unbiased group assignments.
Numbers can be generated through software, online tools, or even mechanical devices.
These generators usually produce numbers within a specific range.
For the exercise involving 20 volunteers, a random number generator would be set to produce 10 unique numbers between 1 and 20.
These numbers correspond to the volunteers' assigned numbers, ensuring each has an equal chance of being selected for the experimental or control group.
experimental group
The experimental group in a study receives the treatment or intervention being tested.
For instance, in the cholesterol medication test, this group gets the experimental drug.
They are compared with the control group to see if there’s a noticeable difference in outcomes.
The idea is to verify if the treatment produces significant effects.
Randomly assigning volunteers to this group ensures that any changes observed are due to the treatment and not other factors.
control group
The control group in a study is essential for comparison.
This group does not receive the experimental treatment but may receive a placebo.
By comparing this group with the experimental group, researchers can determine if the treatment itself is effective.
Random assignment helps make the groups statistically similar, isolating the treatment as the only variable.
In our example, the volunteers who aren't assigned to the experimental group make up the control group.
This helps researchers understand the natural progression of the condition without the new drug.
volunteers assignment
Assigning volunteers to different groups is a crucial step in any experimental design.
The process involves numbering each volunteer uniquely.
For our example, every volunteer is assigned a number from 1 to 20.
The next step is to use a random number generator to select numbers randomly.
The volunteers corresponding to these numbers make up the experimental group.
The remaining volunteers automatically form the control group.
This method is vital to ensure random and unbiased assignments, making the results reliable and valid.

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Most popular questions from this chapter

Read the following article from the January 20 2005 USA Today. What types of nonsampling errors led to incorrect exit polls? FIRMS REPORT FLAWS THAT THREW OFF EXIT POLLS Kerry backers' willingness, pollsters' inexperience cited By Mark Memmott, USA Today The exit polls of voters on Election Day so overstated Sen. John Kerry's support that, going back to 1988 they rank as the most inaccurate in a presidential election, the firms that did the work concede. One reason the surveys were skewed, they say, was because Kerry's supporters were more willing to participate than Bush's. Also, the people they hired to quiz voters were on average too young and too inexperienced and needed more training. The exit polls, which are supposed to help the TV networks shape their coverage on election night, were sharply criticized. Leaks of preliminary data showed up on the Internet in the early afternoon of Election Day, fueling talk that Kerry was beating President Bush. After the election, some political scientists, pollsters and journalists questioned their value. In a report to the six media companies that paid them to conduct the voter surveys, pollsters Warren Mitofsky and Joseph Lenski, said Wednesday that "on average, the results from each precinct overstated the Kerry-Bush difference by 6.5 (percentage) points. This is the largest (overstatement) we have observed \(\ldots\). in the last five presidential elections." Lenski said Wednesday that issuing the report was like "hanging out your dirty underwear. You hope it's cleaner than people expected." Among the findings: \(\cdot\) They hired too many relatively young adults to conduct the interviews. Half of the 1,400 interviewers were younger than \(35 .\) That may explain in part why Kerry voters were more inclined to participate, since he drew more of the youth vote than did Bush. But Mitofsky and Lenski also found younger interviewers were more likely to make mistakes. \(\cdot\)Early results were skewed by a "programming error" that led to including too many female voters. Kerry outpolled Bush among women. \(\cdot\) Some local officials prevented interviewers from getting close to voters. For future exit polls, Lenski and Mitofsky recommended hiring more experienced polltakers and giving them better training, and working with election officials to ensure access to polling places. Lenski and Mitofsky noted that none of the media outlets they worked for \(-\mathrm{ABC},\) CBS, CNN, Fox News, NBC and the Associated Press-made any wrong "calls" on election night. Representatives of those six are reviewing the report. Many other news media, including USA Today, also paid to get some of the data.

What is replication in an experiment?

Identify the type of sampling used. A small-town newspaper reporter wants to get local reaction to a controversial new film. She waits outside the theater during an afternoon show and, starting with the second, asks every fifth patron leaving how much they liked the movie.

A research objective is presented. For each research objective, identify the population and sample in the study. A quality-control manager randomly selects 50 bottles of Coca-Cola that were filled on October 15 to assess the calibration of the filling machine.

For the studies in Problems \(45-50,\) (a) identify the research objective, (b) identify the sample, (c) list the descriptive statistics, and (d) state the conclusions made in the study. Favorite Presidents A poll commissioned by Washington College and conducted by Schulman, Ronca, and Bucuvalas, February \(7-10,2005,\) surveyed 800 U.S. adults. Asked who was the greatest president, \(20 \%\) of respondents chose Abraham Lincoln, \(15 \%\) Ronald Reagan, \(12 \%\) Franklin Roosevelt, \(11 \%\) John \(\mathrm{F}\). Kennedy, \(10 \%\) Bill Clinton, \(8 \%\) George W. Bush, and \(6 \%\) George Washington. The remaining \(18 \%\) selected other presidents. Washington College concluded that Abraham Lincoln ranks first among U.S. adults as the greatest president. (Source: Associated Press, Feb. 22, 2005)

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