Answer with Explanation:
Average in Temperature in last 30 years in the month of July for Eloy and Arizona=90°
Standard Deviation =2.1°
→It means ,temperature of last 30 years of states Eloy and Arizona lie between , 90°-2.1° to 90°+2.1°= 87.9° to 90°.
→→Average of last five Summers, for Eloy and Arizona=92°
a=2.5%
Calculating , the reduction ,which is equal to 2.5% from 92

→89.70° lies between ,87.9° to 90°.
So,we can confidently assert that→the two averages are probably same.
Option D: The average for the last five years fits with the 30-year average.