select the correct answer from the drop - down menu. the mean midday temperature recorded in june in a city…

select the correct answer from the drop - down menu. the mean midday temperature recorded in june in a city in south california is 36°c, and the standard deviation is 3°c. the number of days in the month of june is 30. assuming the data is normally distributed, the number of days in june when the midday temperature was between 39°c and 42°c is
Answer
Answer:
4
Explanation:
Step1: Calculate z - scores
For $x = 39$, $z_1=\frac{39 - 36}{3}=1$; for $x = 42$, $z_2=\frac{42 - 36}{3}=2$.
Step2: Find probabilities
Using the standard - normal distribution table, $P(1<Z<2)=P(Z < 2)-P(Z < 1)$. $P(Z < 2)=0.9772$, $P(Z < 1)=0.8413$, so $P(1<Z<2)=0.9772 - 0.8413=0.1359$.
Step3: Calculate number of days
The number of days $n = 0.1359\times30\approx4$.