Question

a survey asked a random sample of students if they estimated they spent more or less than an hour a day on social media.

• 45 seventh graders were surveyed.
• 28 eighth graders estimated they spent more than an hour.
• 47 eighth graders were surveyed.
• 43 total students estimated they spent less than an hour.

fill in the missing values in the table below.

social media

	more	less	total
8th grade
total

Explanation:

Step1: 7th grade total

It is given that 45 seventh - graders were surveyed. So the total for 7th grade is \(45\).

Step2: 8th grade more

It is given that 28 eighth - graders estimated they spent more than an hour. So the value for 8th grade (more) is \(28\).

Step3: 8th grade total

It is given that 47 eighth - graders were surveyed. So the total for 8th grade is \(47\).

Step4: 8th grade less

Since the total number of 8th - graders is \(47\) and the number of 8th - graders who spent more than an hour is \(28\), then the number of 8th - graders who spent less than an hour is \(47−28 = 19\).

Step5: Total less

It is given that 43 total students estimated they spent less than an hour.

Step6: 7th grade less

Since the total number of students who spent less than an hour is \(43\) and the number of 8th - graders who spent less than an hour is \(19\), then the number of 7th - graders who spent less than an hour is \(43−19=24\).

Step7: 7th grade more

Since the total number of 7th - graders is \(45\) and the number of 7th - graders who spent less than an hour is \(24\), then the number of 7th - graders who spent more than an hour is \(45 - 24=21\).

Step8: Total more

The number of students who spent more than an hour is \(21 + 28=49\).

Step9: Total total

The total number of students surveyed is \(45+47 = 92\) (also \(49 + 43=92\)).

Answer:

Social Media	More	Less	Total
8th grade	28	19	47
Total	49	43	92