The median waiting time for the emergency room last month is 10 minutes, and the mean waiting time is 12 minutes.
The median is the middle value in a dataset when it is ordered from least to greatest. In this case, since the data is presented in a frequency table, we need to find the cumulative frequency that corresponds to the middle of the dataset. The cumulative frequency for the median is 50% of the total number of observations.
In this example, the total number of observations is the sum of the frequencies, which is 20. The cumulative frequency for the median is 10. Thus, the median waiting time is the midpoint of the group with a cumulative frequency equal to or just greater than 10. Looking at the table, this corresponds to a waiting time of 10 minutes.
The mean (average) waiting time can be calculated by summing up the product of each value and its frequency and then dividing by the total number of observations. For this dataset, the calculation is as follows:
![\[ \text{Mean} = (\sum (x_i \cdot f_i))/(N) \]](https://img.qammunity.org/2024/formulas/mathematics/high-school/75xvhf0ad8xut307tymyczjlbfvv6uo3qr.png)
where
is the midpoint of each interval,
is the frequency, and
is the total number of observations. Substituting the values from the frequency table into this formula, the mean waiting time is calculated to be 12 minutes.
In summary, the median waiting time is 10 minutes, indicating that 50% of patients waited 10 minutes or less. The mean waiting time is 12 minutes, providing an average representation of the waiting times across all patients.