Because of a typographical error, The Washington Post incorrectly reported yesterday the degree to which A&P's new brandless products will cost less than the chain's better quality house brands. The story should have said that the new products will cost 10 to 15 per cent less than the better quality house brands.

Given a choice, will Washingtons opt for lower quality groceries if they can save between 10 and 40 percent at the checkout counter?

A&P, the area's third largest food chain, which has 48 stores, is going to find out. Last week it introduced a brandless or no-frills line of 14 products, their "Economy Corner" groceries. Informal tests of the entire line conducted by The Washington Post show that these products are of at least adequate quality and do represent substantial savings in many cases.

With the "Economy Corner" line - in white wrappers with black lettering to emphasize the no-frills aspect of the products - A&P has joined 20 to 30 other supermarkets across the country, including some of the more profitable, in an effort (however small) to lessen the pain of checking out at the cash register.

But are shoppers here so affluent they are willing to pay more for higher quality? This is a claim often made by local supermarket executives in an effort to explain the area's consistently high food prices. (See accompanying story on food editors annual national pricing survey.)

Even with such a small selection, the APPARENT savings on A&P's generic items are substantial. The market basket of 14 generic items cost $11.26 compared to $20.41 for the nationally advertised brands and $15.40 for the chain's house brands.

The "real" savings on some items may be somewhat less dramatic because a greater quantity is needed to perform the same function. The dish detergent, for instance, doesn't make as many suds as a more expensive brand-name detergent; the suds don't last as long as they don't do as many dishes. But the price differential between the nationally advertised brand and the generic is so great ($1 a quart) that the saving is substantial.

With edible products, the savings are more obvious. Even when drained weight (the weight of the canned fruits or vegetables without the liquid) rather than the net weight is compared, the canned generic products proved consistently cheaper than the nationally advertised brands and, with one exception which was one sale, less expensive than house brands, too.

In return for these lower-priced vegetables, what must purchasers forego in addition to fancy packaging? The vegetables are standard rather than choice grade, which means they are supposed to be more mature and therefore less tender. Their color, size and shape are less likely to be uniform. Their nutritional value is said to be the same as their more expensive counterparts. Flavor, perhaps a matter of personal preference, is said to be not as good.

In the informal test some of these generalizations proved correct; others did not.

The four cans of generic vegetables were compared with Ann Page, A&P's house brand (which the chain says is the equivalent of nationally advertised brands) and Del Monte.

WHOLE KERNEL CORN: The appearance among the three was fairly similary. All were about equally tender. The house brand was the sweetest; the generic the least tasty. Because the generic was a more mature corn, it contained 30 calories more per half cup than the other two.

CREAM-STYLE CORN: There was also a substantial difference in calorie count between the generic, house brand and national brand. Again, because a more mature corn has more carbohydrates, a cup of Del Monte corn contained 160 calories; the other two had 220 calories per cup.

The generic had the least flavor and contained the fewest kernels of corn. The national brand had the greatest number of whole kernels but they were more mature and therefore not as tender or sweet as the house brand.

here were also some differences in the amounts of other nutrients, but that seemed 'o balance out: The one with more vitamin C had less vitamin A and vice versa.

PEAS: The national brand had the smallest, tenderest peas with the lightest color. The generics were the darkest in color but not as tough as the house brand. Both of those are described on the label as "mixed sizes." None of them was particularly sweet. Nutritionally they were quite similar.

GREEN BEANS: The generic beans were labeled "mixed cut and short cut." The can also contained a number of bean ends with the strings. They were also paler in color. The taste of all of them was essentially the same - canned.

On a drained weight basis, generic whole kernel corn was 35 cents for 16 ounces. Ann Page was 49 1/2 cents. Del Monte was 56 cents.

Generic creamed-style corn was 27 cents for 16 ounces. Ann Page was 24 cents (on sale); Del Monte was 37 cents.

Generic green beans were 52 cents for 16 ounces. Ann Page was 74 cents; Del Monte was 78 cents.

Generic peas were 42 cents for 16 ounces, Ann Page 57 cents, Del Monte 57 cents.

MACARONI AND CHEESE: The generic had a milder cheese flavor (the sharper the cheese, the greater the cost), but it was not necessarily less appealing. It contained 3/8 ounce less cheese sauce mix and 3/8 ounce more macaroni than the others. All contained artificial color.

The generic package was 27 cents; Ann Page was three for 89 cents or 30 cents each; Kraft was three for $1 or 34 cents each.

FACIAL TISSUES: The generics were equally as soft as Kleenex.

Generic facial tissue was 45 cents for 200 two-ply sheets.Ann Page was 53 cents. Kleenex was 69 cents.

BATHROOM TISSUE: The generic tissues were substantially rougher than the others but certainly not in the same category as those one encounters in Europe. The generic are not perfumed, which some people may consider a plus.

Adjusting for different square footage per package, the prices were: four rolls of generic tissue, 79 cents; four rolls of A&P, $1.35: four rolls of Charmin, $1.03, which included a manufacturer's 5-cents-off sale.

PAPER TOWELS: The generic were lighter in weight, and, according to A&P, "will handle light cleaning and polishing jobs effectively."

Using equivalent square footage of paper towels, the generic cost 55 cents. Ann Page was 60 cents; Scott was 79 cents.

TRASH CAN LINERS: The generics are made of lighter weight plastic and the company brochure notes: "Care should be taken in using them for disposal of glass-ware and sharp-edged items." But the nationally advertised bags appeared to tear as easily if a finger is put through them.

Generic trash bags cost $1.73. Ann Page was $2.19 and Glad was $2.39.

FABRIC SOFTENER: The generic is single strength instead of concentrated, as is Downy, and the company recommends using twice as much. But two quarts of the generic product sell for 59 cents. Ann Page was 69 cents. Downy was $2.19.

BLEACH: All bleaches are the same. The generic costs 59 cents. Ann Page was 85 cents. Clorox was 99 cents.

LAUNDRY DETERGENT: The generic contains none of the chemicals which "whiten" (bleach) clothes or help remove heavy soil. It cost $1.19; Ann Page was $1.47; Tide was $1.83.

DISH DETERGENT: The generic costs 59 cents a quart: Ahoy, the house brand is 79 cents and Ivory is $1.59

DOG FOOD: The generic dog food is described as "chewier," but it contains the same nutrients as other dog food. A&P says this is one of the fastest-moving items in the other cities where they are selling generic. The generic cost $3.89, Daily (housebrand) $5.49 and Purina $6.99.

Where are these savings coming from? According to a company official, neither the plain labeling nor the lack of advertising contributes much to the savings on generic. Costs are lower, he said, because the products are shorn of their frills and are of lesser quality. This, however, would not account for the significant difference in price between Clorox and the generic bleach as they are exactly the same composition. But marketing name-brand products adds a lot to costs, as much as 20 to 30 percent, according to A&P.

Initial response to A&P's generic, which first appeared in the stores last Wednesday, has been "extremely good," according to a store official. Two days after the products were put on sale, the shelves in some stores had to be restocked four times. Now the company is waiting to see if those people who bought last week will come again.

Is Washington ready for no-frills shopping? A&P hopes so. Safeway thinks so. They will introduce their version of nofrills - something between a house brand and a generic - later this summer.