The Mean Green Party Machine

"The purpose of our meeting today," the chairperson began, "is to answer our final question."

"How much should we charge for a slice of pizza?"

"So I ask," she continued, "how much would you pay for a slice of pizza?"

What would be a fair price to charge for a slice of:
Cheese Pizza
Pepperoni Pizza
Supreme Pizza
"I wonder how we could find the average cost of a slice of pizza?" spoke Susan. \|

Susan, Peggy, and John discuss their ideas.

"Susan and I were talking about this earlier, " said Peggy. "Why don't we use pictographs again to divide the cost of one large pizza evenly between the 12 slices?" "You've got to be kidding!" exclaimed John. Do you know how long it will take to divide all those coins between 12 slices of pizza?"

	Do you agree with Peggy or John?
Choose one and explain your answer. \|

Mike has a better plan! "There IS an easier way", cried Mike, as he pulled a green calculator out of his folder. "This calculator can find the average, or the mean, of any data. Let me show you how it works!"

"Just like when we added up the totals and used a pictograph to evenly divide them, this calculator adds up (+) the data and divides (/) it for us to find the mean. I like to call in my mean, green machine!''

"My mean, green machine uses the following operating procedures," Mike explained.

We can find the mean!

Use the blue words on the right of the screen. Click on each blue word to see an example of how the calculator uses these procedures to find the mean.
|

As data is entered, the calculator uses addition to find the totals for each set of data. Then, the calculator uses division to find the mean of the data.	DATA
	ADDITION
	TOTALS
	DIVISION(/)
	MEAN

"Let me get this straight," spoke Marie, our chairperson. First we use to find the TOTALS. Then we use in order to find the mean number of pizza slices eaten by each person at the party. Is this right?" "You've got it!, said Mike. "Now let's give it a try!"

"We'll use the calculator, and follow the operating procedures you have just reviewed for us."

If you need some help getting started, click on this picture.

Some of us were confused at the answer we saw on the machine.

36 slices divided
by 14 people =

2.57142857143 slices per person

Mike explained that to use a calculator, you have to understand what the mean really means.

Type in what you think a mean
of 2.57142857143 slices per person really means.
|

"Well," said Peggy, "the number 2.5714285 starts out with 2.5 just like the mean we found when we used the pictographs."

I wonder...
"But remember we had a piece left over," said Susan. "I wonder what one slice shared between 14 people would look like on the ?"

Susan then wrote down the following:
35 slices/14 people	=	2.5 slices
+1 slice /14 people	=	0.071428571429*
36 slices/14 people	=	2.5714287143
*Notice that the calculator rounds
0.071428571429 to
0.07142857143! \|

"Oh, I get it!" cried John, "but I wonder if the other averages that we found were just as close?"

Use the

and round answers to the nearest tenth place!

PICTOGRAPH	DATA		CALCULATOR
The girls ate 1.5 slices of pizza, with 1/2 slice left over.	# of Slices	8	The mean number of slices eaten by the girls was
	# of Girls	5
On average, the boys ate 3 slices of pizza, with 1 slice left over.	# of Slices	28	The mean number of slices eaten by the boys was
	# of Boys	9
\|

"Thanks to Mike, we now have a simpler way to find the average, I mean the mean, of the data! So let's put this mean, green machine to use and find the average cost of a slice of pizza! I called Pizza Hut after our last meeting and got the following price information," she continued.

Pizza	# of Slices	Price
Cheese	12	$6.99
Pepperoni	12	$6.99
Supreme	12	$13.99*
"Notice that the price of a supreme pizza* is different from the others!" \|

"Before we begin, let's choose the division sentence we must enter into the mean, green machine to find the average cost of each of the first two pizzas."

12 slices /$6.99

$6.99/ 12 slices

"NOW we are ready to find the mean."

Answers have been rounded to the nearest hundredths place.
Pizza	# of Slices	Price	Price per slice
Cheese	12	$6.99
Pepperoni	12	$6.99
Supreme	12	$13.99*
*Remember, this price is different! \|

We found that the mean pizza price per slice was:
Pizza Slice	Price
Cheese	$0.58
Pepperoni	$0.58
Supreme	$1.17

One committee member argued that it was NOT worth our time and effort to order supreme pizzas.
Explain why you agree or disagree.

A survey will be used to find a fair price.

Based on the data, we decided to only order cheese and pepperoni pizzas. To find a fair price to charge for each slice, we planned to conduct a survey.

Between now and the next meeting, we will ask our friends and classmates the following question.

"If a slice of pizza costs $0.58, what do you think would be a fair price to charge?
The data we collect will be used to help us make our decision. Check the price that you think would be fair.

$0.60
$0.65
$0.70
$0.75
$0.80
$0.85
$0.90
$0.95
$1.00

Who knows, we might even have to find the mean of the data to help us answer this question! But that's okay, because the mean allows us to summarize the data into one number, AND one number is a lot easier to read than all that data!

Feel free to join us in our next meeting, when we discuss how to graph and read "All That Data!"