The owner of an auto repair shop studied the waiting times for customers who arrive at the shop for an oil change. The following data with waiting times in minutes were collected over 1-month. 2; 5; 10; 12; 4; 4; 5; 17; 11; 8; 9; 8; 12; 21; 6; 8; 7; 13; 18; 3
Using classes of 0-4, 5-9, and so on, construct:
a. The frequency distribution.
b. The relative frequency distribution.
c. The cumulative frequency distribution.
d. The proportion of customers needing an oil change who wait 9 minutes or less.

Solve the problem by using a venn diagram a group of students were surveyed about their taste in music. they were asked how they like three types of music: rock, country western and jazz. the results are summarized below: no one dislikes all three types of music. six like all three types of music. eleven don’t like country western. sixteen like jazz. three like country western and jazz, but not rock. six don’t like rock. eight like rock and country western. seven don’t like jazz. how many students were surveyed?