A group of researchers wanted to know if there was a difference in average yearly income taxes paid between residents of two very large cities in the Midwestern United States. The average for the first city was $6,505 and for the second city, it was $6,511. The difference provided a $P$-value of 0.0007. The difference is __________ because the $P$-value is small.
cannot be determined with the information given
not statistically significant
biased
statistically significant