Central Tendency/SD
Find the mode.
1,7,7,2,3,5,6,7
What is 7?
A survey of a city's residents is conducted by asking 20 randomly selected people at a grocery store whether the city should impose a beverage tax.
Residents who do not shop at the store are underrepresented, so the sample is biased.
What is biased?
A researcher asks students the average number of hours of sleep they get per night and examines whether the amount of sleep affects students grades.
What is an observational study?
The host of the radio show wants to know the listeners favorite bands. He asks listeners to call the radio station and tells him their favorite bands.
What is self-selected?
Find the median. 2,4,4,6,6,6,7,8
What is 6?
A survey of students at a school is conducted by asking 30 randomly selected students in an all-school assembly whether they walk, drive, or take the bus to school.
No group is overrepresented or underrepresented, so the sample is not likely to be biased.
What is unbiased?
A park employee wants to know if latex paints is more durable that non latex paint. She paints 50 benches with latex paint, and 50 with non latex paint.
What is experiment?
The owner of a lawn care company wants to know if his clients are satisfied with the companys service. He decides to ask 15 clients, randomly chosen from a list of his 32 clients, for their opinions of the company's service.
What is simple random?
Find the range. 7,3,5,4,2,9,16,12,10
What is 14?
On the first day of school, all of the incoming freshman attend an orientation program. The principal wants to learn the opinions of the freshman regarding the orientation program. He decides to ask the first 25 freshman that he sees.
What is Biased. A convenience sample is not likely to be representative of the population.
A researcher wants to know if a soil additive makes a fern grow more quickly. He grows one specimen in treated soil and one in untreated soil.
What is experiment?
The manager of a credit union wants to know whether its members utilize the online services offered on the credit union's Web site. He randomly selects 20 members registered as local patrons of each at the five branches of the credit union to call and ask whether they use the online services.
What is stratified?
Find the mean to the nearest thousandths. 9,4,7,8,5,8,24,5
What is 8.875?
The manager of a city bus system wants to know if the people who ride the buses are satisfied with the service. She decides to post mail-in surveys on each of the city's buses.
What is biased? The sample is not likely to be representative of the population because only people with a strong feeling one way or the other wil choose to respond to the survey.
To find out whether car accidents are more likely on rainy days, a researcher records the weather conditions during 50 randomly selected accidents for the past year.
What is observational study?
The human resources manager at a business wants to know how satisfied the company's employees are with their jobs. She surveys the 20 people who sit closest to her office.
What is convenience?
Find the variance and standard deviation.3,3,4,5,5
What is 0.8 and 0.89?
A writer for a travel magazine wants to learn tourists' opinions about the nightlife in a city. She decides to visit some of the tourist attractions in the city on a Thursday morning. She plans to ask the first 50 tourists she meets for their opinions.
What is unbiased? Some of the tourists who experience the night life in a city are not likely to be visiting tourist attractions the next morning.
In a survey of 80 students, 25 said that they planned on attending the pep rally. The school has 550 students. Predict the number of students who plan to attend the pep rally.
What is 172 students?
You class officers are planning a dance, and they want to know if they should hire a disc jockey or a live band. They decide to survey every tenth students as he or she leaves at the end of the school day.
What is systematic?