To find the relative frequency of a non-defective unit, we first need to determine how many of the units are functioning (defective) out of the total checked.
- Total units checked: 500
- Non-functioning (defective) units: 25
To find the functioning (non-defective) units: \[ \text{Functioning units} = \text{Total units} - \text{Defective units} \] \[ \text{Functioning units} = 500 - 25 = 475 \]
Next, we calculate the relative frequency of a non-defective unit: \[ \text{Relative frequency} = \frac{\text{Functioning units}}{\text{Total units}} = \frac{475}{500} \]
Now, we simplify the fraction \( \frac{475}{500} \):
- Both 475 and 500 can be divided by 25.
Dividing the numerator and denominator by 25: \[ \frac{475 \div 25}{500 \div 25} = \frac{19}{20} \]
Thus, the relative frequency of a non-defective unit is: \[ \frac{19}{20} \]
The correct answer is: Start Fraction 19 over 20 End Fraction.