# Statistics AS maths helpWatch

Announcements
Thread starter 3 years ago
#1
Hi there - could someone please help me with the following question:

"A group of 60 children were each asked to choose an integer value between 1 and 9 inclusive. Their choices are summarised in the table below:

Value Chosen | Number of children
1 | 3
2 | 4
3 | 5
4 | 10
5 | 12
6 | 13
7 | 7
8 | 4
9 | 2

Calculate the mean.

I would like to know why the mean is worked out as [sum of x * Frequency] / frequency and not [sum of x]/n ... I thought that this looked like discrete data and not continuous/ grouped data so can't understand why we are using the former formula... Sorry if I'm missing something basic. Thanks again
0
3 years ago
#2
number of children = f, so it needs to be sum of xf divided by the sum of f, that's as well as I can explain it, sorry if it isn't much use
0
Thread starter 3 years ago
#3
(Original post by phishingrhod)
number of children = f, so it needs to be sum of xf divided by the sum of f, that's as well as I can explain it, sorry if it isn't much use
Hi - thanks so much for your quick response. Just wondering though- which wouldn't it be 60/9 = 6.7 (1dp)? just a tad confused as the stats book suggests you should only use the xf/f formula for continuous/ grouped data - and this is discrete data - unless I'm missing something basic?
0
3 years ago
#4
tbh, I'm not sure as to why, but now whenever I see this sort of question, I go for the xf/f by instinct, but I suppose it's the amount (/frequency) of children picking a certain number, which means that the mean number chosen would be 303/60=5.05

Best bet is, if a particular group of people are CHOOSING something, take what they choose as being x, and the number of times that x is chosen is f, that's what seems to work for me

sorry if this hasn't been much help, again
0
Thread starter 3 years ago
#5
(Original post by phishingrhod)
tbh, I'm not sure as to why, but now whenever I see this sort of question, I go for the xf/f by instinct, but I suppose it's the amount (/frequency) of children picking a certain number, which means that the mean number chosen would be 303/60=5.05

Best bet is, if a particular group of people are CHOOSING something, take what they choose as being x, and the number of times that x is chosen is f, that's what seems to work for me

sorry if this hasn't been much help, again
Great, thank you so much
0
X

new posts

### 867

people online now

### 225,530

students helped last year
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### University open days

• University of Dundee
Mon, 26 Aug '19
• University of Aberdeen
General Open Day Undergraduate
Tue, 27 Aug '19
• Norwich University of the Arts
Sat, 31 Aug '19

### Poll

Join the discussion

#### How are you feeling about GCSE Results Day?

Hopeful (215)
12.49%
Excited (157)
9.12%
Worried (306)
17.77%
Terrified (382)
22.18%
Meh (173)
10.05%
Confused (37)
2.15%
Putting on a brave face (238)
13.82%
Impatient (214)
12.43%