A research assistant randomly selected 75 undergraduate students from the list of all students enrolled in the psychology-degree program at a large university. She asked each of the 75 students, “How many minutes per day do you typically spend reading?” The mean reading time in the sample was 89 minutes, and the margin of error for this estimate was 4.28 minutes. Another research assistant intends to replicate the survey and will attempt to get a smaller margin of error. Which of the following samples will most likely result in a smaller margin of error for the estimated mean time students in the psychology-degree program read per day?
CONCEPTS: MEASURES of VARIABILITYI
1. STANDARD DEVIATION = HOW MUCH VARIABILITY EXITS FROM THE MEAN IN A SET OF VALUES
2. STANDARD ERROR of the MEAN or MARGIN of ERROR = an ESTIMATE of how MUCH VARIABILITY between the SAMPLE MEAN and the POPULATION MEAN
Which of the following samples will most likely result in a smaller margin of error for the estimated mean time students in the psychology-degree program read per day?
N = 75; reading Mean 89 minutes; margin of error (MOE) = 4.28 minutes
Aim to decrease the MOE? SO the other research assistant will need to INCREASE THE SAMPLE size
