Question

Select all of the statements that are true for representative samples. 

• Simple random sampling is used to collect the sample. 

• The size of the sample is greater than 30 to ensure greater accuracy in the results of the study. 

• Every member of the population has an equal probability of being selected to participate in the study. 

• The relevant characteristics of the population are included accurately in the members of the sample. 

• The intended results of the study are unbiased and can be generalized to the population of interest.

Select the reasons why the mean and median do not provide useful information about the center of a distribution of nominal data.

• Nominal data can only be continuous, and, therefore, the mean and the median cannot be calculated.

• For nominal data, the values cannot be placed in rank order, and, therefore, the median cannot be calculated.

• The median reflects the number that appears most often in a data set and therefore is not useful for nominal data.

• Nominal data can contain outliers, and, therefore, the mean is not a good measure of center.

• For nominal data, the values cannot be added together, and, therefore, the mean cannot be calculated.

Answer 1

(1)

A representative sample is a small subset of the large population that seeks to accurately reflect the character of the population.

Random sampling is used to draw a representative sample. For instance if half of the population is female then a sample should consist of 50 % females, approximately, sampled randomly to obtain a representative sample.

Therefore, the statement true for the representative sample is "Simple random sampling is used to collect the sample."

(2)

Nominal data are the type of data that are required to label variables without assigning any quantitative value. It cannot be ordered or measured.

Nominal data are continuous in nature.

Although all continuous data has meant, median, and mode but nominal data only has a mode to provide information about the center of the distribution.

Therefore, the correct statements are the second statement and the fifth statement.