Concept explainers
A researcher wants to describe the effectiveness of a new program (compared to the old program) for teaching reading to elementary school children. Describe how this study could be done as a posttest-only nonequivalent control group design. Next, describe how this study could be done as a nonexperimental pretest-posttest design.
How the above study can be conducted as a posttest-only nonequivalent control group design and nonexperimental pretest-posttest design.
Introduction:
A posttest-only nonequivalent control group design compares two nonequivalent groups of participants. One group is observed after receiving the treatment and the other group is measured at the same time but receives no treatment.
A nonexperimental pretest-posttest design compares two nonequivalent groups. One group is measured twice, once before and once after the treatment and the other group is measured at the same times but no treatment is given.
Answer to Problem 8E
Solution:
The post-test-only nonequivalent control group design and nonexperimental pretest-post-test design is possible and explained as follows.
Explanation of Solution
- For post-test only nonequivalent control group design: There are two groups taken, mostly two different sections from the same class of the elementary school children. One group is treated as per the new program and one group is treated as per the old program (control group). The results are examined after the completion of both the programs, and the results are compared. The groups are examined only after the treatment is complete.
- For nonexperimental pretest-post-test design: Here two groups are considered from the different sections of the elementary school. They are examined for factors like reading ability, IQ, interest in reading, etc. before the treatment is given. One group is then treated as per the new program and the other group (control group) is treated as per the old program. The results are compared with the study. The groups here are examined both before and after the treatment.
Conclusion:
The nonexperimental pretest-posttest design is a better approach to this study as it eliminates the threats to internal validity.
Want to see more full solutions like this?
Chapter 10 Solutions
RESEARCH METHODS-W/ACCESS >CUSTOM<
- You’re scrolling through Instagram and you notice that a lot of people are posting selfies. This piques yourcuriosity and you want to estimate the percentage of photos on Instagram that are selfies.(a) (5 points) Is there a “ground truth” for the percentage of selfies on Instagram? Why or why not?(b) (5 points) Is it possible to estimate the ground truth percentage of selfies on Instagram?Irrespective of your answer to the previous question, you decide to pull up n = 250 randomly chosenphotos from your friends’ Instagram accounts and find that 32% of these photos are selfies.(c) (15 points) Determine which of the following is an observation, a variable, a sample statistic (valuecalculated based on the observed sample), or a population parameter.• A photo on Instagram.• Whether or not a photo is a selfie.• Percentage of all photos on Instagram that are selfies.• 32%.(d) (5 points) Based on the sample you collected, do you think 32% is a reliable ballpark estimate for theground truth…arrow_forwardCan you explain this statement below in layman's terms? Secondary Analysis with Generalized Linear Mixed Model with clustering for Hospital Center and ICUvs Ward EnrolmentIn a secondary adjusted analysis we used generalized linear mixed models with random effects forcenter (a stratification variable in the primary analyses). In this analysis, the relative risk for the primaryoutcome of 90-day mortality for 7 versus 14 days of antibiotics was 0.90 (95% Confidence Interval [CI]0.78, 1.05).arrow_forwardIn a crossover trial comparing a new drug to a standard, π denotes the probabilitythat the new one is judged better. It is desired to estimate π and test H0 : π = 0.5against H1 : π = 0.5. In 20 independent observations, the new drug is better eachtime.(a) Find and plot the likelihood function. Give the ML estimate of π (Hint: youmay use the plot function in R)arrow_forward
- Can you explain what this analysis means in layman's terms? - We calculated that a target sample size of 3626, which was based on anticipated baseline 90-day mortality of 22% and a noninferiority margin of no more than 4 percentage points, would give the trial 80% power, at a one-sided alpha level of 2.5%, accounting for a maximum of 5% loss to follow-up and for early stopping rules for three interim analyses.-arrow_forwardCan you help me understand this analysis? A 95.7% confidence interval is shown for the intention-to-treat analysis (accounting for alpha spending in interim analyses), and 95% confidence intervals are shown for the other two analyses. The widths of the confidence intervals have not been adjusted for multiplicity. The dashed line indicates the noninferiority margin of 4 percentage points.arrow_forwardTitle: Analyzing Customer Satisfaction for UnileverAs a member of Unilever's Customer Experience Management team, you are responsible forevaluating customer satisfaction levels and monitoring competitive moves. This case studyinvolves analyzing satisfaction data to test two key hypotheses about Unilever's performancerelative to its main competitor, Procter & Gamble (P&G).Unilever’s leadership team has emphasized the importance of customer satisfaction inmaintaining competitive advantage and market leadership. As part of this initiative, yourteam regularly monitors satisfaction scores and benchmarks them against competitors likeP&G.You are tasked with analyzing the provided dataset to answer the following questions:1. Does Unilever’s average customer satisfaction score meet the minimum threshold of2. 75%?Is there no significant difference between Unilever’s overall average satisfaction scoreand P&G’s average satisfaction score?arrow_forward
- Need help answering wuestionarrow_forwardThe following table shows a data set containing information for 25 of the shadow stocks tracked by the American Association of Individual Investors (aaii.com, February 2002). Shadow stocks are common stocks of smaller companies that are not closely followed by Wall Street analysts. Click on the datafile logo to reference the data. DATA file Company DeWolfe Companies Exchange Ticker Symbol Market Cap ($ millions) Price/ Gross Profit Earnings Ratio Margin (%) AMEX DWL 36.4 8.4 36.7 North Coast Energy OTC NCEB 52.5 6.2 59.3 Hansen Natural Corp. OTC HANS 41.1 14.6 44.8 MarineMax, Inc. NYSE HZO 111.5 7.2 23.8 Nanometrics Incorporated OTC NANO 228.6 38.0 53.3 TeamStaff, Inc. OTC TSTF 92.1 33.5 4.1 Environmental Tectonics AMEX ETC 51.1 35.8 35.9 Measurement Specialties AMEX MSS 101.8 26.8 37.6 SEMCO Energy, Inc. NYSE SEN 193.4 18.7 23.6 Party City Corporation OTC PCTY 97.2 15.9 36.4 Embrex, Inc. OTC EMBX 136.5 18.9 59.5 Tech/Ops Sevcon, Inc. AMEX ΤΟ 23.2 20.7 35.7 ARCADIS NV OTC ARCAF 173.4…arrow_forwardThe following table shows a data set containing information for 25 of the shadow stocks tracked by the American Association of Individual Investors (aaii.com, February 2002). Shadow stocks are common stocks of smaller companies that are not closely followed by Wall Street analysts. Click on the datafile logo to reference the data. DATA file Company DeWolfe Companies Exchange AMEX Ticker Symbol Market Cap Price/ Gross Profit Earnings Margin ($ millions) Ratio (%) DWL 36.4 8.4 36.7 North Coast Energy OTC NCEB 52.5 6.2 59.3 Hansen Natural Corp. OTC HANS 41.1 14.6 44.8 MarineMax, Inc. NYSE HZO 111.5 7.2 23.8 Nanometrics Incorporated OTC NANO 228.6 38.0 53.3 TeamStaff, Inc. OTC TSTF 92.1 33.5 4.1 Environmental Tectonics AMEX ETC 51.1 35.8 35.9 Measurement Specialties AMEX MSS 101.8 26.8 37.6 SEMCO Energy, Inc. NYSE SEN 193.4 18.7 23.6 Party City Corporation OTC PCTY 97.2 15.9 36.4 Embrex, Inc. OTC EMBX 136.5 18.9 59.5 Tech/Ops Sevcon, Inc. AMEX ΤΟ 23.2 20.7 35.7 ARCADIS NV OTC ARCAF 173.4…arrow_forward
- The following data show the year to date percent change (YTD % Change) for 30 stock-market indexes from around the word (The Wall Street Journal, August 26, 2013). a. What index has the largest positive YTD % Change? Round your answer to once decimal place. index with a YTD % Change of % b. Using a class width of 5 beginning with -20 and going to 40, develop a frequency distribution for the data. YTD % Change Frequency -20 - -15 -15 - -10 -10 - -5 -5 - 0 0 - 5 5 - 10 10 - 15 15 - 20 20 - 25 30 - 35 c. 1. 2. 3. 4.arrow_forwardThe following data show the year to date percent change (YTD % Change) for 30 stock-market indexes from around the word (The Wall Street Journal, August 26, 2013). Click on the datafile logo to reference the data. DATA file Country Australia Index S&P/ASX200 YTD % Change 10.2 Belgium Bel-20 12.6 Brazil São Paulo Bovespa -14.4 Canada S&P/TSX Comp 2.6 Chile Santiago IPSA -16.3 China Shanghai Composite -9.3 Eurozone EURO Stoxx 10.0 France CAC 40 11.8 Germany DAX 10.6 Hong Kong Hang Seng -3.5 India S&P BSE Sensex -4.7 Israel Tel Aviv 1.3 Italy FTSE MIB 6.6 Japan Nikkei 31.4 Mexico IPC All-Share -6.4 Netherlands AEX 9.3 Singapore Straits Times -2.5 South Korea Kospi -6.4 Spain IBEX 35 6.4 Sweden Switzerland SX All Share 13.8 Swiss Market 17.4 Taiwan Weighted 2.3 U.K. FTSE 100 10.1 U.S. S&P 500 16.6 U.S. DJIA 14.5 U.S. Dow Jones Utility 6.6 U.S. Nasdaq 100 17.4 U.S. Nasdaq Composite 21.1 World DJ Global ex U.S. 4.2 World DJ Global Index 9.9 a. What index has the largest positive YTD %…arrow_forwardDescribe a three step process you choose to determine how many elementary schools there are in the city of 5 million people.arrow_forward
- College Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage LearningGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill
- Big Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin HarcourtHolt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGAL