Answer:
The missing number on the given data set is 12.
Explanation:
Here, the set of data = 18,16_,9,12,23
Let us assume the missing number in the data = m
The mean of the data = 15
Total number of observations = 6
Now, Sum of the data = 18 + 16 + m + 9+ 12+ 23 = 78 + m
Also,
![\textrm{ Mean of the given Data} = \frac{\textrm{Sum of all observation in the data}}{\textrm{Total number of observations}}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9nipe4zqhgmnzvi0gzqmh8szgyesnnlgip.png)
![\implies 15 = (78+ m)/(6) \\or, 15(6) = 78 + m\\\implies m = 90 -78 = 12](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7ud7hvu49wayyqr7b12v44brpx26ur4j09.png)
or, m = 12
Hence, the missing number on the given data set is 12.