A department store has a 'Best buy corner', which is divided into $10 Zone, $20 Zone and $40 Zone(i.e. each item in the $10 Zone is sold at $10, etc.) The table below
shows the number of kinds of items in each zone:
$10 Zone : 22 kinds
$20 Zone : 31 kinds
$40 Zone : 84 kinds
Just in front of the Best buy corner , a slogan is hung :
"Just $20 on average Get your best buy!"
How is this average price of $20 calculated? Why is the slogan misleading?
F.3 Maths plz help 20點!!!
2013-07-21 5:26 am
回答 (5)
2013-07-21 6:34 am
✔ 最佳答案
How is this average price of $20 calculated? There is 3 Zone, The middle of zone is $20 Zone
Why is the slogan misleading?
The real average price
=(10x22+20x31+40x84)/(22+31+84)
=4200/137
=$30.657(corr to 3 sig fig)
So that the slogan is misleading.
參考: 揸油~.~
2013-07-28 3:51 am
1) How is the average price of $20 calculated?
3 kinds of prices are $10, $20 & $40. Therefore, the values are 10, 20, 40. When you consider the MEDIAN, which is the middle one of a set of numbers (when the total is odd, for this case, 3), you will get a value of 20.
2) Why misleading?
2 reasons.
a. Mean
When calculating the average price, mean is usually and commonly used. as a result, considering mean, average price= (22x10+31x20+84x40)/70 = $60.14 (corr to 2 dp)
b. mode
Still, $60.14 cant represent the whole picture, since the majority of the products are in the area od $40 Zone. Therefore, mode can be used here also due to extreme data recorded. ($40 Zone: 84) So, mode =$40
Conclusion:
Both SUITABLE indicator/ calculation method: mean+ mode also not equal to $20 or even near. Therefore, the average price of $20 is absolutely misleading.
2013-07-27 19:52:55 補充：
Sorry for the wrong calculation of mean!
It should be
(4210)/ 137 = $30.73
3 kinds of prices are $10, $20 & $40. Therefore, the values are 10, 20, 40. When you consider the MEDIAN, which is the middle one of a set of numbers (when the total is odd, for this case, 3), you will get a value of 20.
2) Why misleading?
2 reasons.
a. Mean
When calculating the average price, mean is usually and commonly used. as a result, considering mean, average price= (22x10+31x20+84x40)/70 = $60.14 (corr to 2 dp)
b. mode
Still, $60.14 cant represent the whole picture, since the majority of the products are in the area od $40 Zone. Therefore, mode can be used here also due to extreme data recorded. ($40 Zone: 84) So, mode =$40
Conclusion:
Both SUITABLE indicator/ calculation method: mean+ mode also not equal to $20 or even near. Therefore, the average price of $20 is absolutely misleading.
2013-07-27 19:52:55 補充：
Sorry for the wrong calculation of mean!
It should be
(4210)/ 137 = $30.73
2013-07-27 5:39 am
(10x22+20x31+40x84)/(22+31+84)
=4200/137
=$30.657(corr to 3 sig.fig.)
應該係咁
=4200/137
=$30.657(corr to 3 sig.fig.)
應該係咁
2013-07-25 3:19 am
How is this average price of $20 calculated? Why is the slogan misleading?
There is 3 Zone, and the middle of zone is $20 Zone.
The real average price
=(10x22+20x31+40x84)/(22+31+84)
=4200/137
=$30.657(corr to 3 sig.fig.)
As a result, the slogan is misleading.
There is 3 Zone, and the middle of zone is $20 Zone.
The real average price
=(10x22+20x31+40x84)/(22+31+84)
=4200/137
=$30.657(corr to 3 sig.fig.)
As a result, the slogan is misleading.
2013-07-24 9:09 am
The average price of $20 is calculated by summing the prices of each zone and divided by three.i.e. (10+20+40)/3 = 23.333333333 and then round off. Then become $20. But actually there should be more than three kinds of items. There are (84+31+22) = 137 items in total. Actual average price should be higher.So the logan is misleading.
收錄日期: 2021-04-13 19:35:30
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130720000051KK00268