与えられたベクトルの中央値を計算しようとしましたが、試したときにエラーが発生し続けました。
median(returns)
Error in median.default(returns) : need numeric data
> returns
[1] 0.001262733 -0.005048584 -0.009160197 0.010411955 -0.00542421
[6] -0.010982649 -0.005807832 0.000863131 -0.00210823 0.000117543
[11] 0.001319904 0.005307534 0.005246006 0.008469327 0.006006664
[16] -0.001411188 -0.011446652 0.002669714 0.003896259 -0.003060607
[21] 0.006306116 0.000895311 -0.006235211 -0.000856819 -0.00056599
[26] 0.00808345 0.00038652 -0.004070623 0.008398158 -0.005976036
[31] 0.011270873 0.007959499 0.003776885 -0.000591663 0.001163452
[36] 0.005759682 0.000678132 0.000609123 -0.000735042
40 Levels: -0.00056599 -0.000591663 -0.000735042 -0.000856819 ... 0.011270873
dput(returns)
structure(c(25L, 9L, 14L, 39L, 10L, 15L, 11L, 22L, 6L, 18L, 26L,
31L, 30L, 38L, 33L, 5L, 16L, 27L, 29L, 7L, 34L, 23L, 13L, 4L,
1L, 36L, 19L, 8L, 37L, 12L, 40L, 35L, 28L, 2L, 24L, 32L, 21L,
20L, 3L), .Label = c("-0.00056599", "-0.000591663", "-0.000735042",
"-0.000856819", "-0.001411188", "-0.00210823", "-0.003060607",
"-0.004070623", "-0.005048584", "-0.00542421", "-0.005807832",
"-0.005976036", "-0.006235211", "-0.009160197", "-0.010982649",
"-0.011446652", "#DIV/0!", "0.000117543", "0.00038652", "0.000609123",
"0.000678132", "0.000863131", "0.000895311", "0.001163452", "0.001262733",
"0.001319904", "0.002669714", "0.003776885", "0.003896259", "0.005246006",
"0.005307534", "0.005759682", "0.006006664", "0.006306116", "0.007959499",
"0.00808345", "0.008398158", "0.008469327", "0.010411955", "0.011270873"
), class = "factor")