Chapter 7, Problem 23P

Xu and Garcia (2008) conducted a research study demonstrating that 8-month-old infants appear to recognize which samples are likely to be obtained from a population and which are not. In the study, the infants watched as a sample of n = 5 ping-pong balls was selected from a large box. In one condition, the sample consisted of 1 red ball and 4 white balls. After the sample was selected, the front panel of the box was removed to reveal the contents. In the expected condition, the box contained primarily white balls like the sample, and the infants looked at it for an average of M = 7.5 seconds. In the unexpected condition, the box had primarily red balls, unlike the sample, and the infants looked at it for M = 9.9 seconds. The researchers interpreted the results as demonstrating that the infants found the unexpected result surprising and. therefore, more interesting than the expected result. Assuming that the standard error for both means is σ_M =1 second, draw a bar graph showing the two sample means using brackets to show the size of the standard error for each mean.