Enter Category Name
Which of the following is the strongest correlation?
-.80
The larger the correlation value is away from 0 (and closer to 1 or -1), the stronger the relationship.
Sampling error can be reduced by:
selecting a larger, representative sample
A researcher wants to examine the effect of different programs on students' reading. The researcher samples the classes of students of a particular program instead of sampling individual students of different programs. What sampling method is this?
Cluster Sampling
A researcher finds a moderate positive correlation between students' high school grade point averages and the income level of their parents/guardians. Which of the following conclusions could be inferred from these data findings?
Students whose parents have higher income levels tend to have higher grade point averages, whereas students with low-income parents tend to have lower gpa.
The standard error of the mean:
is the standard deviation of the distribution of sample means.
The standard error is the standard deviation of the sample means around a population mean.
The standard deviation of the population σ is 5, and the researcher selects 100 people from the population multiple times to get the sample means. What is the standard error of the sampling means?
.50
A study finds a very strong relationship between percentage body fat and number of minutes spent in aerobic activity each week. Which of the following would be the most likely correlation value?
Consider carefully how higher numbers of minutes exercising would relate to the percentage of someone's body that is fat content.
-.76
-.76 is the most plausible value. First, a very strong relationship means that the correlation value is large (a number that is close to either -1.0 or 1.0). Additionally, percentage body fat would be negatively correlated with number of minutes in aerobic exercise per week. The more one exercises, the lower one's body fat percentage, typically.
Which sampling procedure randomly selects participants from subgroups of a population in order to obtain a sample that has a similar proportion of participants from within certain categories (such as ethnic groups) as the distribution in the population?
stratified random sampling
Stratified Random Sampling is the selection of participants to meet a proportional representation among defined subgroups, with the use of probability selection procedures (random sampling) within subgroups.
A researcher distributes survey to his friends and get the data. What sampling method is this?
Convenience sampling
What is the relationship between cholesterol level and the average number of fat grams consumed daily? Enter your answer as a decimal (e.g., .32 or -.58).
Cholesterol Fat Grams consumed
160 20
240 36
200 44
150 28
180 22
.63
The means are 186 and 30 for cholesterol and fat grams, respectively. If you compute the correlation using the data as a population, the standard deviations are 32 and 8.94. The covariance is 180. The correlation would be 180/(32*8.94) = .6289.
If you consider the data to be a sample, the standard deviations are 35.78 and 10, and the covariance is 225. The correlation would be 225/(35.78*10) = .6289.
You are comparing attitudes of undergraduate students in four program areas about the use of technology in courses. You plan to obtain a sample of 400 students by selecting the first 100 students available for surveying in each of four program areas: business, education, engineering, and computer science. The type of sampling procedure you are using is:
quota sampling
Quota sampling is the sampling of subjects from predetermined subgroups at a specified proportion - however quota sampling is defined as obtaining subjects through the use of non-probability methods. If we had used random sampling for each group, we would have been using Stratified Random Sampling.
Use the following data to evaluate the relationship between height and weight of a group of male high school basketball players. Calculate the correlation between the players? heights and weights.
Height Weight
John 70" 180
Mark 73" 195
Eric 72" 202
Kent 72" 190
Ty 73" 188
Joel 69" 175
Fred 75" 200
.82
You are selecting a sample of 300 middle school students from the middle schools in Fort Smith, Arkansas. You desire a representative sample of the Fort Smith middle school student population, however given the procedure you are using, there are special needs students in the school district that have no chance of being selected for the sample. Which of the following statements are true:
all of the below:
The sample may not be representative of the population.
There is a risk of inappropriately generalizing results from the sample to the target population.
The sample has been chosen using a nonprobability sampling method given that not all members of the population have a chance of being selected.
If all members of a population do not have a non-zero chance of being selected for a sample (note that each subject doesn't have to have an EQUAL chance of being selected, but they DO have to have a known chance of being selected if the sample is to be representative), then there is no evidence to indicate that the sample is representative and generalizations to the population are at-risk.