Stats Chapter One Quiz

Determine whether the variable is qualitative or quantitative. Explain your reasoning. Parcel tracking numbers

The variable is qualitative because tracking numbers are attributes or labels.

Determine whether the variable is qualitative or quantitative. Explain your reasoning. Favorite film

The variable is qualitative because a favorite film describes an attribute or characteristic.

The temperatures (in Celsius) of air samples taken simultaneously over a large city are shown below 16.3 19.7 18.9 18.7 20.9 17.5 18.3 19.8 18.4 Determine whether the data are qualitative or quantitative and identify the data​ set's level of measurement.

Are the data qualitative or​ quantitative? Quantitative What is the data​ set's level of​ measurement? Interval

Suppose a survey of 505 women in the United States found that more than 55% are the primary investor in their household. Which part of the survey represents the descriptive branch of statistics? Make an inference based on the results of the survey.

Choose the best statement of the descriptive statistic in the problem. 55% of women in the sample are the primary investor in their household. Choose the best inference from the given information. There is an association between U.S. women and being the primary investor in their household.

Determine whether the statement is true or false. If it is​ false, rewrite it as a true statement. A statistic is a measure that describes a population characteristic.

False. A statistic is a measure that describes a sample characteristic.

Determine whether the statement is true or false. If it is​ false, rewrite it as a true statement. More types of calculations can be performed with data at the nominal level than with data at the interval level.

False. More types of calculations can be performed with data at the interval level than with data at the nominal level. Your answer is correct.

Determine whether the statement is true or false. If it is​ false, rewrite it as a true statement. Using a systematic sample guarantees that members of each group within a population will be sampled.

False. Using a stratified sample guarantees that members of each group within a population will be sampled.

A survey of 2003 third- to​ twelfth-grade students found that they devoted an average of 1 hour and 26 minutes per day to studying for exams. Identify the population and the sample.

Identify the population. The time spent per day on studying for exams by all​ third- through​ twelfth-graders Identify the sample The time spent per day on studying for exams by the 2003 third- through​ twelfth-graders sampled

Observational studies are sometimes referred to as natural experiments. Explain what this means.

In an observational​ study, a researcher measures characteristics of interest of a part of a population but does not change existing conditions.

Determine if the survey question is biased. If the question is​ biased, suggest a better wording. How often do you exercise during an average month?

No, because it does not lead the respondent to any particular answer.

Determine if the survey question is biased. If the question is​ biased, suggest a better wording. Why is eating ice cream bad for​ you?

The question is biased. The wording​ "How do you think eating ice cream affects your​ health?" would be better.

Determine whether the study is an observational study or an experiment. Explain. To study the effects of social media on​ teenagers' brains, researchers showed a few dozen teenagers photographs that had varying numbers of​ "likes" while scanning the reactions in their brains.

The study is an experiment, because it applies a treatment to the teenagers.

Determine whether you would take a census or use a sampling to collect data for the study described below. If you would use a​ sampling, determine which sampling technique you would use. Explain. The most popular chain restaurant among the 65 employees of a company.

The study is a census, because the population is small enough for it to be practical to record all of the responses.

Determine whether you would take a census or use a sampling to collect data for the study described below. If you would use a​ sampling, determine which sampling technique you would use. Explain. The average age of 105,000 online movie rental subscribers.

The study would use a sampling. The study would use simple random sampling because it would be easy for the company to randomly select a portion of its subscribers.

Determine whether the variable is qualitative or quantitative. Explain your reasoning. Hair color

The variable is qualitative because color describes an attribute or characteristic.

Determine whether the value is a parameter or a statistic. The average age of men who have walked on the moon was 39 years, 11 months, 15 days

Parameter

Determine whether the data set is a population or a sample. Explain your reasoning. The age of each resident in an apartment building.

Population, because it is a collection of ages for all people in the apartment building.

The masses (in grams) of a sample of a species of fish caught in waters of a region are shown below 25.3 25.2 23.4 25.4 24.3 27.7 23.5 23.4 22.5 Determine the level of measurement of the data set. Explain your reasoning

Ratio. The data can be ordered and differences between data entries are​ meaningful, and a zero entry is an inherent zero.

Identify the sampling techniques​ used, and discuss potential sources of bias​ (if any). Explain. After a tsunami, a disaster area is divided into 150 equal grids. Thirty of the grids are​ selected, and every occupied household in the grid is interviewed to help focus relief efforts on what residents require the most.

What type of sampling is​ used? Cluster sampling is​ used, since the disaster area is divided into​ grids, and some of those grids are selected and everyone in those grids is interviewed. What potential sources of bias are​ present, if​ any? Certain grids may have been much more severely damaged than others. The grids that are selected may not be representative in terms of damage. Certain grids may have been much more severely damaged than others. Severely damaged grids may have fewer occupied households.

A pharmaceutical company wants to test the effectiveness of a new allergy drug. The company identifies 250 females​ 30-35 years old who suffer from severe allergies. The subjects are randomly assigned into two groups. One group is given the new allergy drug and the other is given a placebo that looks exactly like the new allergy drug. After six​ months, the​ subjects' symptoms are studied and compared. Answer parts​ (a) through​ (c) below.

​(a) Identify the experimental units and treatments used in this experiment. The experimental units are the​ 30- to​ 35-year-old females being given the treatment. The treatment is the new allergy drug. (b) Identify a potential problem with the experiment design being used and suggest a way to improve it. There may be a bias on the part of the researcher if the researcher knows which patients were given the real drug. (c) How could this experiment be designed to be a​ double-blind? The study would be a​ double-blind study if both the researcher and the patient did not know which patient received the real drug or the placebo.

What technology format could be used to generate six random numbers between 1 and 800?

​RandInt(1,800,6​)