Answer:
p=0.1971
Step-by-step explanation:
-Let X be the normally distributed random variable with mean=1050kWh and standard deviation=218kWh.
-We use the z-test to test for the probability of mean consumption being between 1100kWh and 1225kWh as:
[tex]P(1100<X<1225)=P(\frac{1100-\mu}{\sigma}<\frac{X-\mu}{\sigma}<\frac{1225-\mu}{\sigma})\\\\=P(\frac{1100-1050}{218}<Z<\frac{1225-1050}{218})\\\\=P(0.2294<Z<0.8028)\\\\=P(Z<0.8028)-P(Z<0.2994)\\\\=0.7881-0.5910\\\\=0.1971[/tex]
Hence, the probability of mean consumption being between 1100 and 1225kWh is 0.1971