into1) To find those center measures, let's check if the data are organized
2) They are already. So let's proceed to calculate the Mean.
a) Mean
Note that the mean is found by the sum of the observations over the number of it.
b) The Median Since there are 6 observations then we can find the Median this way:
As it is an even number of observations, we pick the half (3rd and add to 4th observation)
c) The Mode. The Mode is the most common number, repetitive, in this case, the mode is 23.
2.) If a 90 yrs old person joins the class :
a) The Mean is going to be 32. 57
b) The median will remain the same because in an odd number of observations the median is going to be a number that divides the data in two halves, in this case, the number 23 is in the middle between the other ages.
c) The Mode will remain the same: 23