review
In a poll, 1,003 adults in a country were asked whether they favor or oppose the use of "federal tax dollars to fund medical research using stem cells obtained from human embryos." Among the respondents, 48% said that they were in favor. Identify the population and the sample.
-pop -All adults in the country -sample -The 1,003 adults selected
In a frequency distribution , the class width is the distance between the lower and upper limits of a class
False. In a frequency distribution, the class width is the distance between the lower or upper limits of consecutive classes.
Class boundaries ensure that consecutive bars of a histogram touch.
True
What is the difference between a frequency polygon and an ogive?
A frequency polygon displays class frequencies while an ogive displays cumulative frequencies
What is the difference between class limits and boundaries?
Class limits are the least and greatest numbers that can belong to the classClass boundaries are the numbers that separate classes without forming gaps between them. For integer data, the corresponding class limits and class boundaries differ by 0.5
After constructing a relative frequency distribution summanzing IQ scores of college students, what should be the sum of the relative frequencies
If percentages are used, the sum should be 100%. If proportions are used, the sum should be 1.
Determine whether the underlined numerical value is a parameter or a statistic. Explain your reasoning. Upper A poll of all 2000 students in a high school found that Modifying 94 % with underline of its students owned cell phones.
Parameter, because the data set of all 2000 students in a high school is a population .
What is the difference between relative frequency and cumulative frequency?
Relative frequency of a class is the percentage of the data that falls in that class, while cumulative frequency a class is the sum of the frequencies of that class and all previous classes
The midpoint of a class is the sum of its lower and upper limits divided by two
True
Why should the number of classes in a frequency distribution be between 5 and 20?
number of classes in a frequency distribution is not between 5 and 20may be difficult to detect any patterns.
What are some benefits of representing data sets using frequency distributions?
organizing the data into freq dist. may make patterns within the data more evident
Determine whether the underlined value is a parameter or a statistic. The average score for a class of 28 students taking a calculus midterm exam was Modifying 72 %
parameter
Identify the population and the sample. Describe the sample data set. A survey of 176 law firms in a country found that the average hourly billing rate for partners was $656
population - all law firms in the country sample- the law firms that were surveyed sample data- The average hourly billing rate for partners of 176 law firms was $656
Suppose a survey of 910 business owners found that more than 28 % bought flood insurance. Which part of the survey represents the descriptive branch of statistics? Make an inference based on the results of the survey.
stat-28% of business owners in the sample bought flood insurance best infer-Most business owners do not buy flood insurance
Determine whether the underlined number is a statistic or a parameter. Upper A sample of professors is selected and it is found that Modifying 45 % with underline own a vehicle.
statistic because the value is a numerical measurement describing a characteristic of a sample
Suppose a survey of 581 women in the United States found that more than 57% 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.
statistic- 57% of women in the sample are the primary investor in their household. best inference-There is an association between U.S. women and being the primary investor in their household.
Determine whether the data set is a population or a sample. Explain your reasoning. The salary of each baseball player in a league.
Population, because it is a collection of salaries for all baseball players in the league.
Determine whether the data set is a population or a sample. Explain your reasoning. The number of garages for each house on a street.
Population, because it is a collection of the number of garages for all houses on the street.
Determine whether the data set is a population or a sample. Explain your reasoning. The number of cars for 10 households in a neighborhood of 30 households
Sample, because the collection of the number of cars for 10 households is a subset of all households in the neighborhood.
What are some benefits of using graphs of frequency distributions?
It can be easier to identify patterns of a data set by looking at a graph of the frequency distribution
A study of 805 senior citizens shows that participants who exercise regularly exhibit less of a decline in the cognitive ability than those who barely exercise at all. From this study, a researcher infers that your cognitive ability increases the more you exercise. What is wrong with this type of reasoning?
The inference 'may incorrectly' imply that exercise 'increases' a person's cognitive ability. The study shows 'a slower decline' in cognitive ability.
Determine whether the underlined number describes a population parameter or a sample statistic. Explain your reasoning. Modifying Sixty minus two of the 92 passengers aboard an airship survived an explosion.
The number is a population parameter because it is a numerical description of all of the passengers that survived.
Determine whether the underlined number describes a population parameter or a sample statistic. Explain your reasoning. A survey of 2208 adults in a country found that Modifying 80 % think that militant terrorists are a major threat to the well-being of their country.
The number is a sample statistic because it describes the people in a sample, which is a subset of all of the people in the country.
An ogive is a graph that displays relative frequencies .
The statement is false. An ogive is a graph that displays cumulative frequencies.
