Sampling types
Every student in RHS names are put in a hat. Three of the students names are drawn to win a new iPad. This is an example of _________ sampling.
What is simple random sampling?
A survey question was asked - "Why is drinking milk good for you?" Pick whether this question would lead to an overestimate or underestimate of the results about milk.
What is overestimate?
A college counselor would like to select a simple random sample of all 525 students in the college. She uses the numbers from 001 to 525 to number the students in a college database and then uses a random number table to choose her sample of 30. What numbers correspond to the first 3 students chosen? 06385 61327 51790 63618 23145 46124 20031
What is 063, 132, 182?
A farm-product manufacturer wants to determine if the yield of a crop is different when the soil is treated with three different types of fertilizers. Fifteen similar plots of land are planted with the same type of seed but are fertilized differently. At the end of the growing season, the mean yield from the sample plots is compared. The experimental units are __________.
What is plots of land?
A recent study showed that tea drinkers have lower stress levels than coffee drinkers. Tea drinkers are known to have a higher proportion of yoga practitioners than coffee drinkers, and they exercise on average two hours per week more than their coffee-drinking counterparts. The term used to describe these additional factors are ____________.
What is lurking variables?
The students in 4th period statistics are lined up in front of the room. The teacher picks a random starting point. Every 5th student was picked after that. This is an example of _________ sampling.
What is systematic sampling?
Call-in radio shows that solicit audience participation in surveys on controversial topics (abortion, affirmative action, gun control, etc.) are examples of __________ bias.
What is voluntary bias?
The purpose of an _________ is to determine the effect of the independent (explanatory) variable on the dependent (response) variable.
What is the experiment?
Suppose a consumer group wants to test 12 cake pans to see which works the best (bakes evenly). It will test aluminum, glass, and plastic pans in both gas and electric ovens. The factors are _______.
What is cake pans and types of ovens?
A company wants to study the effectiveness of a new pain relief medicine. They recruit 100 volunteers who suffer chronic pain.
They assign each subject a number from 1 to 100 and use a random number generator to assign the first 50 subjects selected to the treatment group. The remaining 50 subjects are assigned to the control group.
Completely randomized design
The employees of a company are split into two groups, men and woman. In each of the groups, 100 individuals are chosen at random to ask about their recent raise. This is an example of _______ sampling.
What is stratified random sampling? Remember with cluster sampling you take all the members from the chosen groups. In a stratified sample you group then sample again in each group.
Before the 1936 US presidential election, a popular poll predicted that Alfred Landon would comfortably win against Franklin D. Roosevelt. The poll randomly sampled people from sources like telephone and car registration records, but the country was in an economic crisis, so many voters without those luxuries were not included in the poll.
Which type of bias does this scenario best describe?
Undercoverage
Suppose a consumer group wants to test 12 cake pans to see which works the best (bakes evenly). It will test aluminum, glass, and plastic pans in both gas and electric ovens. The levels are _______ and the number of treatments are ___.
What is 3 types of pans (aluminum, glass and plastic) and 2 types of ovens (gas and electric)? and What is 6?
Suppose a consumer group wants to test 12 cake pans to see which works the best (bakes evenly). It will test aluminum, glass, and plastic pans in both gas and electric ovens. The response variable is _______.
What is how evenly the cakes bake?
A company wants to study the effectiveness of a new pain relief medicine. They recruit 100 volunteers who suffer chronic pain.
Half of the 50 males are randomly assigned to the treatment group, and the other half are assigned to the control group. The same method is used to randomly assign half of the 50 females to the treatment group and the other half to the control group.
What type of experiment design is this?
Randomized block design
After a hurricane, a disaster area is divided into 200 equals 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. This is an example of _________ sampling.
What is cluster sampling?
Valerie manages a team of 30 employees at a large company. She wants to survey members of her team on her performance as their manager. She holds an individual meeting with each of her team's members and asks them the same set of questions. Valerie finds that 83% of her employees rate her performance as "outstanding."
Name the type of bias, and whether 83% would be an underestimate or overestimate.
Response bias, overestimate
__________ reduces bias by spreading any uncontrolled confounding variables evenly throughout the treatment groups.
What is randomization?
A farm-product manufacturer wants to determine if the yield of a crop is different when the soil is treated with three different types of fertilizers. Fifteen similar plots of land are planted with the same type of seed but are fertilized differently. At the end of the growing season, the mean yield from the sample plots is compared. The explanatory variables (factors) are _______.
What is types of fertilizers?
A group of researchers wants to study the effect of listening to music at different volumes on driving reaction times. They recruit 100 volunteers.
While music plays in the car at one of two volume levels, each subject encounters a number of signs, some of which require braking, and their reaction times are recorded. The subjects repeat the experiment at the other volume level. The order of the conditions is randomly assigned for each subject.
What type of experiment design is this?
What is matched pairs?