Answer: 0.5
Explanation:
The probability density function for x that uniformly distributed in interval [a,b] :
We assume that the weight loss for the first month of a diet program varies between 6 pounds and 12 pounds and is spread evenly over the range of possibilities, so that there is a uniform distribution.
Let x be the weight loss for the first month of a diet program.
Density function =
Now , the probability of the given range of pounds lost is less than 9 pounds :
![=\int^(12)_(9)\ f(x)\ dx\\\\= \int^(12)_(9)\ (1)/(6)\ dx\\\\= (1)/(6)[x]^(12)_(9)\\\\=(1)/(6)(12-9)=0.5](https://img.qammunity.org/2019/formulas/mathematics/college/1vib703mx7ee18pzcwp92lmt0b4zfv5la0.png)
Hence, the required probability = 0.5