Given data:
The given table.
The expression for the average temperature is,

Thus, the value of x is 86 degree Fahrenheit.
Answer: 235
Step-by-step explanation:
The formula to calculate the sample size :-

Given : Estimated proportion 
Margin of error : 
Significance level : 
Critical value : 
Now, the required sample size will be :-


Hence, the required minimum sample size = 235