why is the median function returning 0

[karenchusam]

I'm trying to calculate to median of a integer, but it keeps returning zero.

So I first use the pipeline and filter some rows in my dataset. In the pr variable there are 288 numbers stored.

pr <- data_raw %>% 
    filter(date == "2012-10-06") %>% 
    pull(steps)
pr

  [1]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
 [38]   0   0   0   0   0  40  11   0   0   0   0   0   0   0   0   0  19  67   0   0   0   0   0   0   0   0   0   0   0   0   0  27   0   0   0   0   0
 [75]   0  36  50  38   0   4  42  14   8 135 172 124  31  52   0 104 170  58   0   0  75   0   0 211 321 149   0  82  94 225 216 199  50 187  30   0  65
[112] 173  43   0   0   0   0   0   0   0  16  26   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0  95  64   7  33  72 221 439 519 440
[149] 394  97  71  10  87 443 500 465 485 351 515 511 506 486 171  12  24  42 140  15   0  43  67  48   0   0   9  31  30  64 115  25   0  27   0   0   0
[186]   0   0   0   0   0   0   0  27  27   0   0   9   0   0  54  35   0  49   0   0   0   0  93   0   0  13   0   6  12   0   0  34  77 173 370 402 504
[223] 485 437 526 264   0  35 124  93   0   0   0   0   0   0   0   0   0   0   0   0  33 118   0   6   0 262  33  46  35   0   0   0   0   0   0   0   0
[260]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0

I calculated the mean of pr which seems ok. But the median keeps returning zero.

length(pr)
[1] 288

class(pr)
[1] "integer"

mean(pr)
[1] 53.54167

median(pr)
[1] 0

Does someone know why is this happening?

Thank you

[bloosmore]

Based on your data, it looks like the median is in fact 0?

Are you instead asking about finding the median of the non-zero values?

[StatSteph]

The median is 0. Look at the data in this way sorted, the middle number is 0. There are 288 items and the 144th and 145th item are 0.

pr <- c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 40, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 19, 67, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 27, 0, 0, 0, 0, 0,
0, 36, 50, 38, 0, 4, 42, 14, 8, 135, 172, 124, 31, 52, 0, 104, 170, 58, 0, 0, 75, 0, 0, 211, 321, 149, 0, 82, 94, 225, 216, 199, 50, 187, 30, 0, 65,
173, 43, 0, 0, 0, 0, 0, 0, 0, 16, 26, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 95, 64, 7, 33, 72, 221, 439, 519, 440,
394, 97, 71, 10, 87, 443, 500, 465, 485, 351, 515, 511, 506, 486, 171, 12, 24, 42, 140, 15, 0, 43, 67, 48, 0, 0, 9, 31, 30, 64, 115, 25, 0, 27, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 27, 27, 0, 0, 9, 0, 0, 54, 35, 0, 49, 0, 0, 0, 0, 93, 0, 0, 13, 0, 6, 12, 0, 0, 34, 77, 173, 370, 402, 504,
485, 437, 526, 264, 0, 35, 124, 93, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 33, 118, 0, 6, 0, 262, 33, 46, 35, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)

length(pr)
#> [1] 288

sort(pr)
#>   [1]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
#>  [19]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
#>  [37]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
#>  [55]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
#>  [73]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
#>  [91]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
#> [109]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
#> [127]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
#> [145]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
#> [163]   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
#> [181]   0   0   4   6   6   7   8   9   9  10  11  12  12  13  14  15  16  19
#> [199]  24  25  26  27  27  27  27  30  30  31  31  33  33  33  34  35  35  35
#> [217]  36  38  40  42  42  43  43  46  48  49  50  50  52  54  58  64  64  65
#> [235]  67  67  71  72  75  77  82  87  93  93  94  95  97 104 115 118 124 124
#> [253] 135 140 149 170 171 172 173 173 187 199 211 216 221 225 262 264 321 351
#> [271] 370 394 402 437 439 440 443 465 485 485 486 500 504 506 511 515 519 526
median(pr)
#> [1] 0

^{Created on 2021-08-03 by the reprex package (v2.0.0)}

[karenchusam]

Thanks for the answer!!! I completely forgot that I need to sort or order the data. My bad