Use the Normal to Model the Distribution of Sample Means

question 13

Multiple Choice

Use the Normal to model the distribution of sample means.
-In a metal fabrication process, metal rods are produced that have an average length of 20.5 feet with a standard deviation of 2.3 feet. A quality control specialist collects a
Random sample of 30 rods and measures their lengths. What is the probability of
Observing a sample mean greater than 21 feet?

• A) 0.3830
• B) 0.8830
• C) 0.4778
• D) 0.5222
• E) 0.1170

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Definitions:

Purine

A nitrogen-containing compound that is one of the two types of bases found in DNA and RNA, the other being pyrimidine.

Pyrimidine

A nitrogenous base found in nucleic acids, characterized by a single ring structure, such as cytosine, thymine (in DNA), and uracil (in RNA).

Diploid

Having two of each type of chromosome characteristic of the species (2n).

Chromosomes

Structures consisting of DNA and proteins, found in the nucleus of cells, carrying genetic information in the form of genes.