Questions from Statistics

Q: Researchers are interested in testing whether a video game that is designed

Researchers are interested in testing whether a video game that is designed to increase brain activity actually works. To test this, they plan to randomly assign subjects to either the treatment group...

Q: We counted ones, twos, threes, fours, and fives

We counted ones, twos, threes, fours, and fives from a few lines of a random number table, and we should expect to get equal numbers of each. (We ignored the sixes, sevens, eights, nines, and zeros.)...

Q: Speed skating is a sport in which it is important to have

Speed skating is a sport in which it is important to have a suit that minimizes wind drag as much as possible, as the difference between winning and losing a race can be as small as a thousandth of a...

Q: Suppose you want to compare the effectiveness of the flu vaccine in

Suppose you want to compare the effectiveness of the flu vaccine in preventing the flu using one of two different forms: nasal spray versus injection. Suppose you have 60 subjects available of differe...

Q: Suppose that you want to determine whether the use of one aspirin

Suppose that you want to determine whether the use of one aspirin per day for people age 50 and older reduces the chance of heart attack. You have 200 people available for the study: 100 men and 100 w...

Q: Phubbing is the practice of ignoring one’s companion or companions in order

Phubbing is the practice of ignoring one’s companion or companions in order to pay attention to one’s phone or other mobile device. In the conclusion of a 2017 study published in Personality and Indiv...

Q: Suppose you grow tomato plants in a greenhouse and sell the tomatoes

Suppose you grow tomato plants in a greenhouse and sell the tomatoes by weight, so the amount of money you make depends on plants producing a large total weight of tomatoes. You want to determine whic...

Q: In a 2017 study, researchers investigated the effect of dietary improvement

In a 2017 study, researchers investigated the effect of dietary improvement on adults with moderate to severe depression (Jacka et al. 2017). Subjects were randomly assigned to a treatment group consi...

Q: Repeat the chi-square test (all four steps) from

Repeat the chi-square test (all four steps) from exercise 10.23, but this time assume that you got exactly 20 outcomes in each of the six categories. Refer to the figure. Explain.

Q: Some people believe that it is easier to read words printed on

Some people believe that it is easier to read words printed on colored paper than words printed on white paper. To test this theory, statistics student Paula Smith collected data. Subjects were timed...