Question

14)Find the values at the 30th and 90th percentiles for each data set. 14. 6283 5700 6381 6274 5700 5896 5972 6075 5993 5581

Answer 1

how many numbers are in the data set?

Answer 2

10! @amistre64

Answer 3

i count 10 as well

now a percentile is a division by 100, and is a positional value, the number in a certain position is what we want to find.

1 percentile is equal to 10/100

we want to know what 30 and 90 percentiles are equal to, then we can look in those positions (after sorting of course) to determine the values associated with them

Answer 4

i see one little caveat that will have to be addressed tho, if our percentile has no decimal to it, we need to average things; if it has a decimal we simply round up.

Answer 5

how do i get to that

Answer 6

@amistre64

Answer 7

as explained, 1 percentile = 10/100

how do we find 30 percentiles?

Answer 8

if there had been 14 numbers in the set: then 1 percentile would have been 14/100.

if there had been 3 numbers in the set: then 1 percentile would have been 3/100.

if there had been 42 numbers in the set: then 1 percentile would have been 42/100.

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if n numbers in a data set, then 1 percentile is equal to n/100

Answer 9

if we know '1' of anything, then 30 of them is just adding up 30 of them together right?

Answer 10

yes

Answer 11

then 30 percentile is just 30*10/100, which is equal to 3

now we have to follow a rule of thumb. since 3 has no decimals tacked on to it, we have to take an average of the 3rd and 4th numbers of the SORTed data set

Answer 12

sort the data set from smallest to largest, and then we can simply pick out the positional values associated with these things

Answer 13

thats alot of numbers to sort! lol

Answer 14

1235432 is alot to sort :0

10 is nothing

Answer 15

sort{6283 5700 6381 6274 5700 5896 5972 6075 5993 5581}

http://www.wolframalpha.com/input/?i=sort%7B6283+5700+6381+6274+5700+5896+5972+6075+5993+5581%7D

{5581, 5700, 5700, 5896, 5972, 5993, 6075, 6274, 6283, 6381}

Answer 16

{5581, 5700, 5700, 5896, 5972, 5993, 6075, 6274, 6283, 6381}
^ ^
30th 90th

Answer 17

so its the 90th

Answer 18

or 80th?

Answer 19

not too sure what you mean ....

we are asked to find the values at the 30th and 90th percentiles a data set.

since there are 10 numbers in the data set,
then 1 percentile is equal to 10/100

30 percentile is equal to 30*10/100 = 3
90 percentile is equal to 90*10/100 = 9

now, since we dont have something like 3.3456 or 9.466, we cant just pick the next positions (4 and 10) and be done.

we have to average the 3rd and 4th to find the 30th percentile value
we have to average the 9th and 10th to find the 90th percentile value

Answer 20

okay. my apologies...i am still understanding this concept. it isnt too easy for me atleast. so the answer is 30th and 90th?

Answer 21

@amistre64

Answer 22

30th and 90th are positions, they are not values.

we want values

Answer 23

okay

Answer 24

{5581, 5700, 5700, ___ ,5896, 5972, 5993, 6075, 6274, 6283, ___ , 6381}
^ ^
30th 90th

the values we want are not in the data set, we have to define them by the average of the 2 values that are around them

Answer 25

okay so the ones that are above the percentiles are the values

Answer 26

yes, they will represent the values associated with the 30th and 90th percentiles.

Answer 27

2 processes are at work here:

find a position, and define the value that is in that position.

Answer 28

okay! can you answer a couple more? i will close this post

Answer 29

i can try, as long as i can recall the stuff :)

Answer 30

thank you!