Question

ms. bohanon surveyed each of her students about the amount of time they studied for a test. the dot plot shows the results
study time
30 35 40 45 50 55 60 65 70 75 80 85 90
amount (minutes)
which statement is best supported by the data in the dot plot?
a the number of students who studied one hour or more is greater than the number of students who studied less than 45 minutes.
b the difference between the greatest and least amounts of time students studied is one hour.
c the number of students who studied more than one hour is greater than the number of students who studied one - half hour.
d the most common amount of time students studied is 60 minutes.

Explanation:

Step1: Count students per group

• <35 mins: 3 students; 35-40 mins: 2 students; 40-45 mins: 2 students; Total <45 mins: $3+2+2=7$
• ≥60 mins (1 hour): 3 (60) +1 (80)+1(90) =5 students
• Max study time: 90 mins; Min study time: 30 mins; Difference: $90-30=60$ mins =1 hour
• >60 mins: 1+1=2 students; 30 mins (half hour):3 students
• Most common: 30,45 mins (3 students each)

Step2: Evaluate each option

• A: 5 ≥60 <7 <45 → False
• B: $90-30=60$ mins=1 hour → True
• C: 2 >60 <3 30-min → False
• D: 30/45 most common, not 60 → False

Answer:

B. The difference between the greatest and least amounts of time students studied is one hour.