Chapter 4, Problem 10CRE

a.

To determine

To find: The type of experimental design and provided the reason of using it.

Explanation of Solution

Given:

An ultra-long-distance race, as you may figure, is a footrace longer than the 26.2 miles of a long-distance race. Sprinters ordinarily create respiratory diseases after ultra-long-distance race Scientists haphazardly allotted ultra-long-distance runners to get either nutrient C or a fake treatment.

Stratified random samples can be defined as the samples collected using simple random sampling from different strata in a heterogeneous population.

Here sampling method stratified random sample should be used because sample from each group could be selected and then all the selected groups would be equally shown in the chosen sample.

b.

To determine

To explain: The purpose of random assignment

Explanation of Solution

Random assignment is mainly used to create groups and reduce the bias that are affecting the result. Thus, it would be applied to reduced the bias and affect the result.

c.

To determine

To explain: The concept of significance more to the layman in the provided case.

Explanation of Solution

The placebo rate of 68% is significantly higher than the vitamins of 33% which implies that the difference that has been observed that is too large.