Can we predict any price just looking at difficulty charts? Is there any correlation between hash rate and value? At the beginning of June-2017 hash rate was 4,858,754,124 GH/s while difficulty was 678,760,110,082 [1] Bitcoin price was $2,505.13 at that time [2]
[1] https://bitcoinwisdom.com/bitcoin/difficulty
[2] https://coinmarketcap.com/historical/20170604/
In order to demonstrate correlation thesis mentioned above, comparing historical prices against difficulty and hash rate may spark off a conclusion [3]
[3] https://www.bitfinex.com/trading
It is obviously clear on the charts that there is no positive nor negative correlation between those indicators (difficulty vs price & hash rate vs price) Ascending difficulty requires higher hash rates, higher hash rates spend more electricity and need better equipments, in order to cover miners' cost assuming price movements "to the moon" should occur somehow.