In a survey taken in July 1985, of the 2,500 households randomly surveyed from across the United States, the proportion of households having a personal computer was determined to be 11%. The U.S. government census data taken in August 1985 suggested that 11.7% of households in the United States had a personal computer.
Which statement(s) below support the small discrepancy between the sample proportion of households having a personal computer in July 1985 and the population proportion of households having a personal computer in August 1985?
The sample size was too small.
The sample was not truly random.
The data from July 1985 to August 1985 changed substantially.
The sample statistic is nearly equal to the population parameter and will never be exactly equal.
An official Census is a comprehensive survey of the whole nation. It is estimated that in 1985, there were 90 million households in the U.S. A poll of 2,500 households cannot compare, in accuracy, to the official Census of some 90 million households. Therefore, I would say that the discrepancy is due to "The sample size was too small".