Final answer:
The researcher would likely use standard deviation and range to measure the variability in the rating of the variety of Apple's iPads, as these statistics provide measures of spread that indicate how far the data points are from the mean and the overall extent of the ratings.
Step-by-step explanation:
A researcher interested in measuring the variability in the rating of the variety of Apple's iPads would likely consider using both standard deviation and range. These statistics are measures of spread, which show how far the data points are from the mean of the data set. The researcher could use the standard deviation to understand the average distance each rating is from the mean rating, which would give a sense of consistency in the responses. The range would provide information about the extent of the ratings, showing the difference between the lowest and highest values given.