Reference no: EM132377045

1. Companies who design furniture for elementary school classrooms produce a variety of sizes for kids of different ages. Suppose the heights of kindergarten children can be described by a Normal model with a mean of 39.2 inches and standard deviation of 1.9inches.

a. The middle 90?% of kindergarteners are expected to be between ____ inches and _____ inches.

2. Most people think that the? "normal" adult body temperature is 98.6°F. In a more recent? study, researchers reported that a more accurate figure may be 98.2°F. ?Furthermore, the standard deviation appeared to be around 0.9°F. Assume that a Normal model is appropriate.

a. What fraction of people would be expected to have body temperatures above 98.6d°?F?

3. In one season of a football? league, the number of yards gained by each of the 168 wide receivers was recorded. A histogram of the data is shown to the right. The mean is 473 ?yards, with a standard deviation of 341 yards.

According to the Normal? model, 2.5% of receivers are expected to gain fewer yards than 2 standard deviations below the mean number of? yards? Using the 68-95-99.7 rule.

For these? data, what does that? mean?

A. Some of the receivers should gain less than -209 ?yards, but? that's impossible, so the model? doesn't fit well.

B.None of the receivers should gain more than 1155 yards. The model? doesn't fit well because many receivers gained more than 1155 yards.

C. Many more receivers gained 0 yards than the model predicts.? Thus, the model? doesn't fit well.

4. Fuel economy estimates for automobiles built one year predicted a mean of 27.8 mpg and a standard deviation of 5.2 mpg for highway driving. Assume that a Normal model can be applied. Use the 68-95-99.7 Rule.

a. About what percent of autos should get more than 33 ?mpg?