The college is planning to add the food vendor in student union and would like to know what kind of food service the students would prefer. A sample of 120 students is obtained and each student is asked to choose his/her preference from coffee shop, a pizza place, or hamburger grill. The resulting frequency data are given in the table below.
Coffee

Pizza

Hamburger

53

37

30

(a) Do the data point out any significant preferences among the 3 types of food service? Test at the .05 level of significance.
a) Yes, there are important preferences
b) no; there are no important preferences
(b) A similar survey of student population 10 years ago found that coffee shop was preferred through 20% of the students, and pizza and hamburger were each preferred by 40% of students. Find out the expected frequencies for chisquare test.
Coffee 
Pizza 
Hamburger
Do the data indicate a significant change in preferences during the past 10 years?
a) Yes, there has been a significant change in preferences
b) no, there hasn't been any change in the population proportions