Final answer:
The IRS advises keeping financial statements and tax returns for a minimum of three years, but this can extend to seven years in certain cases. For statistical samples, 'X' represents the mean value, such as the mean time taxpayers spend on IRS Form 1040.
Step-by-step explanation:
The question relates to how far back one should keep financial statements and tax returns. According to the Internal Revenue Service (IRS), individuals are generally advised to keep these documents for a minimum of three years, which corresponds to answer choice (a) 3 years. This period covers the typical timeframe the IRS has to audit a tax return. However, there are some situations where you may need to keep these documents longer, such as for tax returns claiming a loss from worthless securities or bad debt deduction, in which case the recommendation is 7 years.
Now, regarding the statistics problem presented, when a random sample of 36 taxpayers is taken, in statistical terms, 'X' typically represents the mean or average value of the sample. If we assume that 'X' is the mean time it takes for these taxpayers to complete IRS Form 1040, based on the information provided, the mean of this sample (X) would be the average amount of time spent by the sampled taxpayers on this activity.