Revision 238246b2-9d1c-48d9-a673-8dc8aa513817 - Code Golf Stack Exchange

# JavaScript (ES6), 55 bytes

Returns `[mean, p_mean, trend]`.

<!-- language-all: lang-javascript -->

 a=>a.map(v=>t=(s+=v,n++)?(t+v)/2:v,n=s=0)&&[s/=n,t,t-s]

[Try it online!](https://tio.run/##dY7RCoMgFIbv9xRehaKVVowanPYg0YW0GhvNYoqv70TZLobB8cDh@78fn9JKPb0fu8nVdpvdAk5CL4uX3LGF3gDWFCxTlJIrNtSSsrr4EzRwkmWDLkExw0yuRzdtSm/rXKzbHS94EAxVDNUjIac/UgciEkRwj/yreUrjgfolOD@QRcQJ2jDkp2Oo9YGwz@EUBz@JJEhNyLZhvNEl4t23OvZGSfza3Qc "JavaScript (Node.js) – Try It Online")