Which data design Each situation described in Exercises 211

Which data design? Each situation described in Exercises 21.1 to 21.4 requires inference about a mean or means. Identify each as involving (1) a single sample, (2) matched Pairs, or (3) two independent samples. The procedures of Chapter 20 apply to designs (1) and (2). We are about to learn procedures for design (3). 21.1 How Sweet It Is. Choose 10 agricultural plots of land located in different regions of the state. Plant half of each plot with one variety of sweet corn and the other with a different variety. Compare the sugar contents of both varieties of corn. 21.2 Exercise and Memory. To examine the effect of physical exertion on the memory of a witnessed event, researchers randomly divided police officers into two groups. One group completed a high-intensity physical assault exercise and the other did no exercise. Both groups were then placed in a live, occupationally relevant scenario. After the scenario, the mean scores on an exam testing recall of what was witnessed during the scenario were compared. 21.3 Smart Phone Battery Life. To check the lifetime of a new battery in a soon-to-be-released smartphone, an engineer surfed the web over 4G continuously, beginning with a fully charged battery, until the battery was drained. The engineer repeated this for a total of 10 times. He compared the results with the lifetime of 12.8 hours for the current battery used in the company\'s smartphone. 21.4 Smart Phone Battery Life, Continued. Another engineer is checking the lifetime of the new battery with a prototype that she just developed. She wants to know how the lifetimes of the new battery and her prototype compare. She measures the lifetime of the new battery and her prototype by continuously surfing the web over 40 until the battery is drained. She repeats this a total of 10 times for each type of battery.

Solution

21.1 Matched pairs -- as the space is divided into two halves and experiments tried with different methods

21.2 Mathced pairs

21.3 a single sample test

21.4 Two independent samples