CHAPTER 1 ELEMENTARY STATISTIC

A research company uses a device to record the viewing habits of about 10 comma 000 ​households, and the data collected today will be used to determinenbspthe proportion of households tuned to a particular children's program.

Cross section study

In a study of a weight loss​ program, 4 subjects lost an average of 50 lbs. It is found that there is about a 31​% chance of getting such results with a diet that has no effect.

No, the program is not statistically significant because the results are likely to occur by chance. Yes, the program is practically significant because the amount of weight loss is large enough to be considered practically significant.

In a poll conducted by a certain research​ center, 1287 adults were called after their telephone numbers were randomly generated by a​ computer, and 50 % were able to correctly identify the president.

Random

In a survey of 757 ​subjects, each was asked how often he or she drank milk. The survey subjects were internet users who responded to a question that was posted on a news website.

Sample

Determine whether the study depicts an observational study or an experiment. Fifty patients with brain cancer are divided into two groups. One group receives an experimental drug to fight cancer, the other a placebo. After two years, the spread of the cancer is measured. The study is an experiment because the researchers control one variable to determine the effect on the response variable.

The study is an experiment because the researchers control one variable to determine the effect on the response variable.

homeowner measured the voltage supplied to his home on 6 days of a given week​, and the average​ (mean) value is 133.9 volts.

the given value is a statistic for the year because the data collected represents a sample