Generally a positive correlation.

But that is not to say that you can expect each individual alt to move in accordance with BTC markets. This used to be the case when the biggest alt out there was LTC (many years ago), but it is entirely different now.

With the current market conditions, you have to consider each alt on a case by case basis. ETH and XRP are moving in entirely different directions - yet, they would both fall under the umbrella category of "large-cap alts".