help with maths! (1 Viewer)

[stressedadfff]

hey guys im super lost with the following could anyone pls help

 

[cossine]

So do you know how the mean, median and mode are calculated?

Just give it a ago see what equations you get.

 

[stressedadfff]

So do you know how the mean, median and mode are calculated?

Just give it a ago see what equations you get.

not the median and mode tbh i only know when its under in the noraml distribution form

 

[stressedadfff]

So do you know how the mean, median and mode are calculated?

Just give it a ago see what equations you get.

i dont know why but i got 0-8 for A, 11 for b and couldnt figure c since i kept getting -ves

 

[cossine]

i dont know why but i got 0-8 for A, 11 for b and couldnt figure c since i kept getting -ves

MODE
The 0-8 is correct however remember k is positive so it would be 1-8

MEDIAN
We need to find the middle value.

The middle value is given by (k + 2 + 9 + 6 + 7)/2

Let just be creative for bit.

If k = 1

Then middle_value = 12.5

meaning the median is 2.5

if k = 2

=> middle_value = 13

meaning the median value is 2

So that is our answer k =2

 

[cossine]

i dont know why but i got 0-8 for A, 11 for b and couldnt figure c since i kept getting -ves

c)

The mean number of children per family

= Total_num_children / Total_num_families

= (0*k + 1*2 + 2*9 + 3*6 + 4*7) / (k+1+2+6+7) =2 # Note we just need to make k the subject

=> (2+18+18+28) = (k+1+2+9+6+7)*2

=> k = (2+18+18+28)/2 -1 -2 - 9 - 6 -7

=> k = 8

Edit forget subtract 9

 

[5uckerberg]

For the mean let's finish this off

First off you do the following for each column multiply the number of families by the number of children. Remember sigma notation is applied. So thus,

k times 0 you know what that is, 0.
2 families with one child, that is just 2 times 1
9 families with 2 children, that is 9 times 2
6 families with 3 children, that is 6 times 3
7 families with 4 children, that is 7 times 4.
Now luckily k is 0 otherwise this would be an interesting question. Here this becomes 2+18+18+28+0=66. We are given the mean is 2 so therefore we have the total number of families and children which is 66 now this question is basically,66/k+2+9+6+7=2, here we swap the k+2+9+6+7 term with 2 and here we should see that 33=k+2+9+6+7. To find k very simple, k=33-2-9-6-7=9.

 

[5uckerberg]

c)

The mean number of children per family

= Total_num_children / Total_num_families

= (0*k + 1*2 + 2*9 + 3*6 + 4*7) / (k+1+2+6+7) =2 # Note we just need to make k the subject

=> (2+18+18+28) = (k+1+2+6+7)*2

=> k = (2+18+18+28)/2 -1 -2 -6 -7

Do you mean k=(66/2)-9-2-6-7?

 

[cossine]

Do you mean k=(66/2)-9-2-6-7?

Yes thank you. I think might be missing the one from two families

 

[stressedadfff]

thank youuu