help with daughters math homework please?

Question

please could someone corfirm if i have provided the correct information for my daughter

mean = the average number of a sequence of number

1, 3, 5, 7, 11, 15

total = 42 / 6 = 7

and median number is the middle or average of the middle two numbers of the sequence

using the sequence above

middle numbers are 5,7 so the median number would be

6

it is nearly thirty years since i done this myself in school any help would be apriciated

Answer 1

You've worked out these anwers correctly but your explanation of working out the median was slightly wrong.

You were right when you said that the mean/average is the sum of the set of scores that you have in a set of results divided by the number of scores that you have. In this case, the average would be 1+3+5+7+11+15 =42/6=7, as you said earlier.

The median is the mid point of the set of scores.

If you have an ODD numbered set of scores, you count along your set of scores until you find the score which has an equal number of scores either side of it and that is your median.

If you have an EVEN set of scores (as you correctly said and worked out), you count along your set of scores until you find TWO scores which have an equal number of scores either side of them and divide these TWO values by 2 (in other words, you're finding the average of these 2 scores). In this case, the two scores with an equal number of scores either side of them are 5 and 7 (5 has 2 scores before it and 7 has 2 scores after it) and 5+7=12/2 =6.

In summary:

Mean=7

Median=6

By the way, if you see the formula N-1 for the mean/median, this means that before you work out the mean and median, you need to take away 1 from the number of scores you have (N=number of scores in a set of results). This is because you can't always be sure that your set of scores are evenly spread out (normally distributed) across the mean/mid point of your set of scores, but don't worry about this point, unless your daughter is studying A Level Maths/Statistics/Psychology. At GCSE Maths level, you don't need to know this. However, I thought that I would explain this principle, as you may have seen this written in a textbook somewhere.

Hope this answer helps!

For further information, click on one of the following websites:

http://www.bbc.co.uk/schools/gcsebitesize/maths/

The BBC GCSE Bitesize revision website

http://www.bbc.co.uk/dna/mbonionstreet/F2468125

Onion Street-The BBC Bitesize revision website forum where you can post questions to teachers on H/W issues like this.

www.s-cool.co.uk

This brilliant website tells you everything you need to know in exams from a wide range of subjects from GCSE to A-Level. If you can't find anything under the GCSE Maths section, this topic also comes up in the AS Psychology section under research methods & data analysis.

Answer 2

To calculate the MEAN, add up all the terms, and then divide by the number of terms in the distribution. So CORRECT.
The MEDIAN of a distribution with a discrete random variable depends on whether the number of terms in the distribution is even or odd. If the number of terms is odd, then the median is the value of the term in the middle. If the number of terms is EVEN, then the median is the average of the two terms in the middle, such that the number of terms having values greater than or equal to it is the same as the number of terms having values less than or equal to it. So CORRECT again.

Answer 3

those definitions are correct, and the third one that often is put with mean and median is:

mode, the most frequent number, so if they were 5, 5, 6, 7, 8, it would be 5

Answer 4

right...for the second one-->
if the number of observations is even, then median is the mean of (n/2)th and (n/2 +1)th observations......
n = 6 thus
3rd and 4th term are 5 and 7.. the mean is 5+7 = 12/2 = 6

Answer 5

yes that is correct.. mean is all the numbers added together divided by the amount of numbers you have which is what you have done.

median is the middle number so that is right too.

the mode (if you need it) is the most common number in the collection.. you haven't got one in that in that series but if any one of those numbers appeared twice then that wouldbe you mode.


hope that helps but sounds like your pretty much there anyway.

:)

Answer 6

both right. This sort of maths is the kind of maths that you remember. I don't really know how much of it you remember, cos I'm still learning maths at school!

Answer 7

http://www.bbc.co.uk/schools/revisewise/maths/data/12_fact.shtml this site will help but the firsts right and i think the second is too save the page and it will help in the future

Answer 8

School was a long time ago for me, but you are right;

Answer 9

you are absolutely correct :-)

amazed at your memory... yu remember your maths for last 30 years !!

Answer 10

yes you done that right,but did you teach working steps correctly, i hope yes. best of luck.