Attorneys general in several states are investigating Wal-Mart on charges that they have made a practice of charging customers the wrong prices, and in doing so, failed to meet the federal standards for price accuracy.

The investigation is based on the findings of two university studies that showed that in almost 87 percent of stores owned by the world’s largest retailer, Wal-Mart, in California, and nearly 85 percent in Michigan, Indiana and Illinois, “failed to meet federal standards for pricing accuracy.”

Federal rules state that for every 100 purchases scanned, no more than two should have the wrong price. The studies report that in Illinois, Michigan and Indiana, 6.4 percent of purchases were priced inaccurately, and in California 8.3 percent of items purchased were priced incorrectly.

The studies, conducted by the University of Illinois and the University of California at Berkeley, analyzed a random selection of Wal-Marts in Illinois, Michigan, Indiana and California. The United Food and Commercial Workers, UFCW, a member of the Change to Win Federation, funded the studies.

“Consumers shouldn’t have to gamble with the price they pay at Wal-Mart stores,” said UFCW spokesperson Paul Blank. “Wal-Mart customers have a right to know whether or not they are paying the wrong price. In at least four states, Wal-Mart may need to change its slogan to ‘Sometimes Low Prices’ if you are lucky.”

The UFCW, which launched the national WakeUpWalMart.com campaign to educate consumers about the practices of Wal-Mart, joined with the National Consumers League to urge attorneys general in all 50 states to launch an immediate, full-scale investigation into Wal-Mart’s pricing practices based on the findings of the studies.

Connecticut’s Attorney General Richard Blumenthal told reporters his office would investigate Wal-Mart’s “culture” of inaccuracy.

WakeUpWalMart.com has launched a national Wal-Mart Consumer Alert for the Holidays. The campaign, which began the Friday after Thanksgiving — the first big shopping day of the season — plans to distribute over one million flyers in at least 36 states and over 102 cities.