Final answer:
The question lacks the necessary information to calculate the percentage remaining for samples Y and Z; it requires the associated z-scores or additional context.
Step-by-step explanation:
The question appears to relate to statistics and z-scores, which are used for describing the position of a raw score in terms of its distance from the mean, measured in standard deviations. There isn't enough data provided to calculate percentages remaining for samples Y and Z. However, based on the options presented and the common statistical concept that:
- About 68 percent of values lie within 1 standard deviation from the mean (z-scores of -1 and +1).
- About 95 percent lie within 2 standard deviations from the mean (z-scores of -2 and +2).
- About 99.7 percent lie within 3 standard deviations from the mean (z-scores of -3 and +3).
These rules come from the empirical rule or the 68-95-99.7 rule, which applies to normally distributed data. To accurately calculate the percentage remaining for samples Y and Z, we would need the associated z-scores or additional context as to what these percentages are referring to.