Question

Can some one explain how to solve this?

Answer 1

probability is a ratio of number matching "success" divided by total number of possibilities

"success" means those cases that match what your are looking for.

Answer 2

for the 1st question (a), the total number of possibilities is the sum of all the different ages.

Answer 3

this is a Q from my statistics class

Answer 4

to answer (a), you need the total number of births 15 to 54
you also need the number between 30 and 39.
get out your calculator and figure those two sums. the ratio is the probabilty

Answer 5

ok i added all the #'s & got 7414

Answer 6

What now?

Answer 7

you also need the number between 30 and 39.

Answer 8

then take the ratio of the that number (30 to 39) over 7414
round to 3 decimal places (that is what they want)

Answer 9

so a) is 0.632?

Answer 10

yes.

notice for (b) you could add up everything that is not 30 to 39 and divide by 7414
or
1 - (a)'s answer = 1 - 0.632

Answer 11

0.368?

Answer 12

yes

for (c) it looks easier to subtract 45-54 from the total, rather than adding up everything less.

Answer 13

ok i subtracted 119 from 7414 & got 7295

Answer 14

This is what i got so far.

Answer 15

Do you understand the major idea?

Probability of some "event" is
\[ \frac{\text{number in the event}}{\text{total number}} \]
to do (a), you found
\[ \frac{\text{number in age bracket 30 to 39}}{\text{total number in all ages}} =\frac{4686}{7414}\]

to do (c), find
\[ \frac{\text{number in age bracket 15 to 44}}{\text{total number in all ages}} \]
can you do that?