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Strange issue with mean, max, and min of vector?

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FsC
FsC 2024년 6월 17일
댓글: Star Strider 2024년 6월 18일
Hello,
I am having an issue with finding the mean max and min of a vector (attached). All values in the vector are positive (increments of time) and less than 1. However, when I test the mean() = -8.0219, max = 9.5770, min = -4.3200e+04. When I try to find() the indices of the min and max, it says that it is 1 but, the value at index 1 is 0.012.
When you test the vector, do you get the same result? Why is it outputting these incorrect values?

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Star Strider
Star Strider 2024년 6월 18일
편집: Star Strider 2024년 6월 18일
See the plotted values —
load('diffT.mat')
whos('-file','diffT')
Name Size Bytes Class Attributes diffT 5370x1 42960 double
% diffT
neg_vals = nnz(diffT < 0)
neg_vals = 1
[lo,hi] = bounds(diffT)
lo = -4.3200e+04
hi = 9.5770
diffT_median = median(diffT)
diffT_median = 0.0170
diffT_mean = mean(diffT)
diffT_mean = -8.0219
figure
plot(diffT)
grid
xlabel('Index')
ylabel('diffT (Everything)')
figure
plot(diffT)
grid
xlabel('Index')
ylabel('diffT (Bounded)')
ylim([min(diffT(1:1000)) max(diffT(1:2000))])
diffT_out = filloutliers(diffT,'nearest'); % Detect & Fill The Outlier
[lo,hi] = bounds(diffT_out)
lo = 0.0130
hi = 0.0210
median_diffT_out = median(diffT_out)
median_diffT_out = 0.0170
mean_diffT_out = mean(diffT_out)
mean_diffT_out = 0.0165
stdev_diffT_out = std(diffT_out)
stdev_diffT_out = 7.1457e-04
figure
plot(diffT_out)
grid
xlabel('Index')
ylabel('diffT\_out')
figure
histfit(diffT_out, 100, 'lognormal')
grid
Your statement ‘All values in the vector are positive’ seems not to be the actual situation. There is one value that is equal to -43200, and that sort of spoils the party. You might want to see how that large negative value managed to get in your ‘diffT’ data.
When in doubt, plot the data!
EDIT — Corrected typographical errors.
.
  댓글 수: 2
FsC
FsC 2024년 6월 18일
이동: Steven Lord 2024년 6월 18일
Thank you for the thorough answer! Now I know to plot in the future
Star Strider
Star Strider 2024년 6월 18일
As always, my pleasure!

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