These values have mean of 17 and standard deviation of about 4.1. If instead we first calculate the range of our data as 25 â 12 = 13, and then divide this number by four we have our estimate of the standard deviation as 13/4 = 3.25.
Plastic marked with an SPI code of 4 is made with low-density polyethylene, or LDPE. LDPE is not commonly recycled, but it is recyclable in certain areas. It tends to be both durable and flexible. It isn't known to release harmful chemicals into objects in contact with it, making it a safe choice for food storage.
Polyethylene is probably the polymer you see most in daily life. Polyethylene is the most popular plastic in the world. This is the polymer that makes grocery bags, shampoo bottles, children's toys, and even bullet proof vests.For such a versatile material, it has a very simple structure, the simplest of all commercial polymers.olyethylene is the most popular plastic in the world. This is the polymer that makes grocery bags, shampoo bottles, children's toys, and even bullet proof vests. For such a versatile material, it has a very simple structure, the simplest of all commercial polymers.