What is the first quarter quartile of having the following probability...
First Quarter Quartile of Probability Density Function
Definition of Probability Density Function
A probability density function (PDF) is a function that describes the likelihood of obtaining a particular value from a continuous random variable. It is a non-negative function that integrates to 1 over its range.
Given PDF Function
f(x) = 1/(-72√3x-10)^2/72
Definition of First Quarter Quartile
The first quarter quartile (Q1) is the value that defines the point at which 25% of the observations lie below it, and 75% of the observations lie above it.
Calculating Q1
- Calculate the cumulative distribution function (CDF) of the given PDF.
- Use the CDF to determine the value of x that corresponds to the 25th percentile.
- Round the value of x to the nearest hundredth to obtain Q1.
Cumulative Distribution Function
The cumulative distribution function (CDF) of a continuous random variable X is defined as:
F(x) = P(X ≤ x)
Integrating the given PDF function from negative infinity to x:
F(x) = ∫(-∞,x) f(t) dt = ∫(-∞,x) 1/(-72√3t-10)^2/72 dt
After solving the integral, we get:
F(x) = (1/2) - (1/2) erf((√3x+10)/(6√2))
Finding the 25th Percentile
We need to find the value of x that corresponds to the 25th percentile, which is the point at which 25% of the observations lie below it. We can use the inverse of the CDF to find this value.
F(x) = 0.25
Substituting the value of F(x) in the CDF equation:
0.25 = (1/2) - (1/2) erf((√3x+10)/(6√2))
After solving for x, we get:
x = -1.12
Calculating Q1
Rounding the value of x to the nearest hundredth, we get:
Q1 = -1.12
Conclusion
The first quarter quartile of the given probability density function is -1.12.