Question

The results for a survey of 120 students who were selected randomly are listed below.

60 students have a cell phone plan with company X
• 36 students have a cell phone plan with company Y
• 24 students do not have a cell phone
The total population of students was 380. Based on the data, what is the best approximation for the total
number of students who have a cell phone plan with company Y? Company X? no cell phone?
​

Answer 1

Company X - 190 students

Company Y - 114 students

No phones - 76 students

Explanation:

1) Find a multiplier to get the ratio from sample to population; to compare the sample to the population

380/120 = 3.16666667 or 3 & 1/6

380 comes from the total population of students and 120 comes from the randomly selected.

2) Use our multiplier to compare the results to the population

People with Company X

• 60 * 3.16667 = 190

People with Company Y

• 36 * 3.166667 = 114

People with no cell phone

• 24 * 3.166667 = 76.0000000001 = 76 (rounded)

Double check

190 + 114 + 76 = 380