Question

(a) In a group of 230 students there are 20 freshman, 113 sophomores, 72 juniors, and 30 seniors. Compute the relative frequency of these events – the event here that of a student belonging to a particular class. Compute the relative frequency of a student being an upper classman (junior or senior). Show the corresponding histogram using relative frequencies for the y-axis, and ordering the groups by seniority on the x-axis.

(b) Assume that it is the first day of class. A freshman has spent 0 years in college, a sophomore 1 year, etc. Compute the mean, median, and mode for the number of years in college in this sample.

Answer 1

The relative frequency of an event is defined as the number of times that the event occurs during experimental trials, divided by the total number of trials conducted.

Relative frequency for freshman = 20/230 =0.087

Relative frequency for sophomores = 113/230 = 0.0491

Relative frequency for juniors = 72/230 = 0.3130

Relative frequency for seniors = 30/230 = 0.1304

Relative frequency for junior or senior = 102/230 = 0.4434

Now we want to find the mean median mode

mean = 0*20+1*113+2*72+3*30/230=1.50

median = middle value which will be 1

mode = 1