A Consumer Advocacy Group Tested the "On-Air" Lifetimes of a Random

question 49

Multiple Choice

A consumer advocacy group tested the "on-air" lifetimes of a random sample of 152 cell phone batteries. The mean lifetime was 2.9 hours with a standard deviation of 0.4 hours. The lifetimes are Approximately bell-shaped. Estimate the number of batteries with lifetimes between 2.5 hours and 3.3 hours.

• A) 103
• B) 144
• C) almost all (greater than 144)
• D) 49

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Definitions:

Fetus Development

The stage of human development in the womb from the ninth week after fertilization until birth, involving significant growth and differentiation of tissues and organs.

Germ Layer

In early embryonic development, one of the three primary layers (ectoderm, mesoderm, and endoderm) that give rise to all tissues and organs of an organism.

Dermis

The layer of skin beneath the epidermis that contains nerve endings, sweat glands, and hair follicles.

Ectoderm

The outermost of the three primary layers of an embryo that develops into the nervous system, skin, and related structures.