Question

Below are the data collected from two random samples of 500 American students on the number of hours they spend in school per day (rounded to the nearest hour):
Meg concludes that students spend a mean of 7 hours in school each day. Tara thinks the mean is 6 hours. Who is correct—Meg or Tara?

Help? I'm not exactly sure how to solve this.

Answer 1

where is the data collected

Answer 2

There it is (:

Answer 3

to find the mean you have to multiply x by frequency

Answer 4

sum (x * frequency of x ) / total sum

Answer 5

Haha I'm kinda just sitting here trying to figure it out. Like, I found the mean of both data samples and they're both 100 but is that even useful information for this answer? Like, 5 hours is closest to the mean but that has nothing to do with it. . .

Answer 6

not quite, the mean is 6

Answer 7

sample A mean =
( 4 * 70 + 5*100 + 6*125 + 7*135 + 8 * 70 ) / ( 70 + 100 + 125 + 135 + 70)

Answer 8

Ah, okay! I thought you were supposed to divide by the number of numbers? (sorry that hardly makes sense)

Answer 9

If you are given just the raw ungrouped data, then you can add them up and divide by total.
Here we are given grouped data in the form of a frequency distribution, so its a little different.

Answer 10

so the first column for sample A is saying , there are 70 people who spend 4 hours a day in school.
if you wanted to convert this to raw data you would have
4,4,4,4,4,4,4..... seventy fours

Answer 11

so we have to modify the formula
Sum x * f / sum x

sample A= ( 4 * 70 + 5*100 + 6*125 + 7*135 + 8 * 70 ) / ( 70 + 100 + 125 + 135 + 70)

Answer 12

ah okay! So I do the same for sample B?

Answer 13

and then see which is the average?

Answer 14

right