Given: To test a car's exhaust fumes, an inspector took six samples. The exhaust samples contained the following amounts of gas in parts per million (ppm); 8,5,7,6,9 and 5. The maximum allowable mean is 6 ppm.
Required: To identify whether the vehicle passed the test.
Explanation: The mean of the data is given by the formula,
![\text{ Mean=}\frac{\text{ Sum of all observations}}{\text{ Total number of observations}}](https://img.qammunity.org/2023/formulas/mathematics/college/mm94wt9vlfqg181k1fejesncjvgrsa63zc.png)
![\text{ Mean=}\frac{\text{8+5+7+6+9+5}}{6}](https://img.qammunity.org/2023/formulas/mathematics/college/yfnrpkkb4lj3tlvej9xglp9f6sqtzqoicw.png)
![\begin{gathered} \text{ Mean=}(40)/(6) \\ \text{ Mean=6.67 ppm} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/bn4iihshy4oxeq7b6gh62dsm7uufggh7hf.png)
Since the maximum allowable mean was 6 ppm and the mean of the sample is 6.67, which is greater than the allowed mean. Therefore the car failed the test.
Final Answer: The car did not pass the test.