Crowdly

The five number summary of the data.

The frequency of data within set intervals of value.

The amount of data overall.

A description of different houses on the market includes the following variables:

monthly utilities bill (e.g. $230.00)
quarterly rates bill (e.g. $540.00)
suburb (e.g. Clayton)
area postcode (e.g. 3800)

Which of the variables are quantitative?

utilities bill and rates bill

area postcode code and suburb

the monthly utilities bill

area postcode, utilities bill and rates bill

all choices represent quantitative variables

The biggest problem with this sample is that it is

To assess the opinion of students about campus safety at your campus of Monash University, a reporter for the student newspaper interviews 15 students she meets walking on your campus late at night who are willing to give their opinion.

Reference: Ref 7-3

probably biased because students walking on campus late at night probably tend to feel safer about doing so than does the student body at large.

none ... there is no problem with the sampling method.

a random sample of students with night classes.

a convenience sample of students in general.

She randomly selects 5 students from French, 5 from German, 5 from Spanish, and 5 from Chinese. What type of sampling design is this approach?

Olivia wants to learn a foreign language. To get an idea of how satisfied other students were after taking a foreign language course, she decides to take a random sample of 20 students.

Systematic sample

Cluster sample

Simple random sample

Stratified random sample

Stratified random sampling

A random sample of 800 airline passengers is wanted from 100 particular flights leaving Sydney Airport. Assume there are 200 passengers aboard each flight.

A numbered list of all 100 x 200 = 20,000 passengers on these flights was obtained. One passenger was drawn from each set of 20,000/800 = 25 passengers. Randomly choose among the first 25 passengers on the list to start, and then choose every 25th passenger until 800 passengers were obtained.

What type of sampling technique is this?

Systematic sampling

Simple random sampling

Cluster random sampling

A survey is based on results from a representative sample, or subset, of the population, not the entire population.

Which of the following statements best describes the main difference between a survey and a census?

A census asks more questions than a survey.

A census always involves an interview in person whereas a survey can also conducted over the phone.

A survey is carried out more frequently than a census.

Does it seem possible or impossible to you that the Nazi extermination of the Jews never happened?

A 1992 Roper poll found that 22% of Americans say that the Holocaust may not have happened. The actual question asked in the poll was:

and 22% responded “Possible.” The results of this poll cannot be trusted because

we do not know who conducted the poll or who paid for the results.

the question is worded in a confusing manner.

nonresponse is present. Many people will refuse to participate, and those that do will be biased in their opinions.

undercoverage is present. Obviously, those people who did not survive the Holocaust could not be in the poll.

A questionnaire on a table at a shopping centre was completed by 100 shoppers.

The results were used to claim that the average amount of money spent by Australians increased from the previous year.

Which one of the following biases makes this survey questionable?

the 10,000 households that did not respond.

Each month the census bureau mails survey forms to 250,000 households asking questions about the people living in the household and about such things as motor vehicles and housing costs. Telephone calls are made to households that don't return the form. In one month, responses were obtained from 240,000 of the households contacted.

Reference: Ref 7-1

The sample is

all the households in the country.

the 250,000 households initially contacted.

the 240,000 households that respond.