Question

In the 1940s, the U.S. Department of Commerce reported a new way to test the tensile strength, in pounds per square inch, of concrete. Several samples of concrete specimens were used to estimate the mean tensile strength of 430 pounds per square inch with a margin of error of 10 pounds per square inch.After the study was published, another group proposes to run the same test on concrete specimens but with samples including many more concrete specimens in each sample. Which of these statements is most likely to be true about the second study?

Answer 1

The samples of concrete used to estimate the mean are said to be several. Therefore, the sample size is big enough to estimate the mean to a reasonably high level of accuracy.

Also, the second study was run with a sample size that is more than the first, therefore the estimate of the mean derived from the second study should even be more accurate than the estimate from the first study.

However, as the estimate from the first study is also of a high level of accuracy, then the margin of error for the second study will likely be around 10 pounds per square inch.

The correct choice is B