If you’re a prospective home buyer, the latest existing-home sales data from the National Association of Realtors is a mixed bag. On the one hand, the number of homes for sale was up 7.3 percent in July from the month before. That’s a much needed improvement, since the lack of homes for sale has been driving home prices higher and fueling competition among buyers. But while inventory has improved, it’s still much lower than normal. And, in July, 89 percent of homes sold were on the market for less than a month. That means, while buying conditions may be improving, the market is still hot. Lawrence Yun, NAR’s chief economist, says the supply of entry-level homes remains particularly low. “We see inventory beginning to tick up, which will lessen the intensity of multiple offers,” Yun said. “Much of the home sales growth is still occurring in the upper-end markets, while the mid-to lower-tier areas aren’t seeing as much growth because there are still too few starter homes available.” Overall, sales of previously owned homes were up 2 percent in July, marking the second straight month of gains.