Question

You observe that the distribution of weights of individuals drawn from a random sample of the United States appears bimodal; there are peaks at 130 lbs. and 165 lbs. You were under the impression that weights follow a normal distribution. Why do you think this distribution differs so much?

Answer 1

The distribution of weights of individuals drawn from a random sample of the United States appears bimodal, possibly due to the presence of different groups or subpopulations within the sample. Factors like age, gender, and ethnicity can also contribute to the bimodal distribution of weights.

Step-by-step explanation:

The distribution of weights of individuals drawn from a random sample of the United States appears bimodal with peaks at 130 lbs and 165 lbs, which is different from the assumption that weights follow a normal distribution. One possible reason for this difference is the presence of different groups or subpopulations within the sample. For example, there may be a group of individuals who are generally smaller in stature and weight, resulting in the peak at 130 lbs, and another group of individuals who are generally larger in stature and weight, resulting in the peak at 165 lbs.

Additionally, factors like age, gender, and ethnicity can also contribute to the bimodal distribution of weights. For instance, if the sample consists of a large proportion of children and adults, who naturally have different average weights, it could lead to a bimodal distribution.

Answer 2

Because of the number of overweight and underweight people

Step-by-step explanation:

The peaks appear because there are significant numbers of overweight and underweight people, compared with a relative small number of people with normal, average weight.

In today's society there are two extremes: the overweight and the underweight people, they make up the largest part of the population and this is why weight does not follow a normal distribution any longer, it concentrates in the peak measurements. To follow a normal distribution, the number of people with average weight would have to be predominant in a society, which is not a case today.