Header file question

The following 3 file program was constructed so I could get advice with
header file inclusion. The program compiles and run fine.

= Funcs.h =============================
#ifndef FUNCS_H
#define FUNCS_H

#include <vector>

double sum(std::vector<double> &vd);

#endif
= Funcs.cpp ===========================
#include "Funcs.h"

double sum(std::vector<double> &vd)
{
   double s = 0.0;

   for(const double &d : vd)
     s += d;

   return s;
}
= Test.cpp ============================
#include <iostream>
#include "Funcs.h"

int main()
{
   std::vector<double> numbers = {1.5, 2.5, 3.5, 4.5};

   std::cout << "The sum is " << sum(numbers) << std::endl;

   return 0;
}
=======================================

1. In Funcs.cpp the file Funcs.h was included since it seems like best
practices for an X.cpp to always include an X.h. However one could
argue that someone reading Funcs.cpp would see the use of the type
vector<double> and therefore #include <vector> should also be there,
even though it is redundant.

2. Same question for Test.cpp. Should #include <vector> be there since
it already comes from #include Funcs.h?

Thank you,
Joe