Question

500mg calcium 1200mg calcium
effective 82 167
not effective 137 59

find the marginal frequency distributions regarding effectiveness.
@fedev80

Answer 1

that's easy ;)

Answer 2

The total of each row and total of each column are the marginal frequencies or marginal distribution

Answer 3

regarding effectiveness, the marginal distribution would be
effective: 82+167
not effective: 137+59

Answer 4

so it would be 249?

Answer 5

or would it be 445?

Answer 6

nope, the marginal distribution is:

effective: 249
not effective: 196

Answer 7

get it?

Answer 8

is the distribution for the 'effectiveness' variable, regardless of the amount of calcium

Answer 9

ok if it asks for the marginal frequency regarding calcium supplement it would be 445?

Answer 10

that's why it's called 'marginal'

Answer 11

no, ot would be:
500mg: 219
1200mg: 226

Answer 12

oh ok I get it thanks

Answer 13

these are the frecuencies regardless of thr effectiveness

Answer 14

is there any possible lurking variables in this data?

Answer 15

445 is the 'joint frecuency' of teh sample

Answer 16

would that be the lurking variables?

Answer 17

would the lurking variables be effective and not effective?

Answer 18

mmmmm...

Answer 19

I think not, a lurking variable would be a third variable that is causing you to think that there's a sirect relationship between the variables

Answer 20

what conclusions could be made regarding the association among the effectiveness of taking a calcium supplement and reducing blood pressure?

Answer 21

for example, gender, maybe the effectiveness is greater not because of the calcium, but because that, as it happened, more man subjects were used for the 1200mg experiments

Answer 22

that is the last question I have

Answer 23

you could say that taking more calcium improves the probability of effectiveness