Question

5. Which of the four methods for handling missing data would tend to lead to an underestimate of the spread (e.g., standard deviation) of the variable? What are some benefits to this method?

6. Calculate the mean, median, and mode (in dollars) (10,7,20,12,75,15,9,18,4,12,8,14)

Answer 1

5) Which of the four methods for handling missing data would tend to lead to an underestimate of the spread (e.g., standard deviation) of the variable? What are some benefits to this method?

1. Listwise or case deletion = Listwise deletion is the most frequently used method in handling missing data, and thus has become the default option for analysis in most statistical software packages. Some researchers insist that it may introduce bias in the estimation of the parameters. However, if the assumption of MCAR is satisfied, a listwise deletion is known to produce unbiased estimates and conservative results. When the data do not fulfill the assumption of MCAR, listwise deletion may cause bias in the estimates of the parameters.

2. Pairwise deletion = Pairwise deletion eliminates information only when the particular data-point needed to test a particular assumption is missing. If there is missing data elsewhere in the data set, the existing values are used in the statistical testing. Since a pairwise deletion uses all information observed, it preserves more information than the listwise deletion, which may delete the case with any missing data.

3. Mean substitution = In a mean substitution, the mean value of a variable is used in place of the missing data value for that same variable. This allows the researchers to utilize the collected data in an incomplete dataset. The theoretical background of the mean substitution is that the mean is a reasonable estimate for a randomly selected observation from a normal distribution

4. Regression imputation = In regression imputation, the existing variables are used to make a prediction, and then the predicted value is substituted as if an actual obtained value. This approach has a number of advantages, because the imputation retains a great deal of data over the listwise or pairwise deletion and avoids significantly altering the standard deviation or the shape of the distribution. However, as in a mean substitution, while a regression imputation substitutes a value that is predicted from other variables, no novel information is added, while the sample size has been increased and the standard error is reduced.

6) Calculate the mean, median, and mode (in dollars) (10,7,20,12,75,15,9,18,4,12,8,14)

The Mean Is: 17$
The Median Is: 12$
The Mode Is: 12$