The given graph shows the distribution of number of years of experience for 25 teachers enrolled in an advanced degree program at a particular university. If a 26th teacher with 2 years of experience is added to the program and to the data set, what will be the effect on the mean and median of the data set?

The correct answer is: The Mean will decrease and the Median will remain the same.

Mean of a frequency distribution =
Median of a frequency distribution = Value of the Observation _______________ (odd number of observations)
Median of a frequency distribution = ____________- (even number of observations).
Data in Ascending order-
25 observations- 1,1,1,1,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,5,5
26 observations- 1,1,1,1,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,5,5
Step-by-step solution:-
In the given data set,
Mean of 25 observations =
Mean of 26 observations =
Hence, Mean has decreased.
Median of 25 observations = Value of the Observation = value of observation
= Value of 13th observation
= 3
Median of 26 observations = value _____________ (even number of observations).



= 3
Hence, Median remains the same.
Final Answer:-
Option C i.e. The Mean will decrease and the Median will remain the same. is the correct Option.