Sampling Techniques and Errors

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Questions and Answers

What is the primary characteristic of stratified sampling?

Samples can be combined regardless of differences between groups.

The population is divided into strata based on a common characteristic. (correct)

All members of the population are treated equally.

Samples are taken from only one group within the population.

What is the first step in the stratified sampling procedure?

Perform a population census.

Divide the population into mutually exclusive strata. (correct)

Select simple random samples from each stratum.

Combine samples from different groups.

Why might researchers choose to use stratified sampling?

It allows for a more homogenous sample.

It simplifies data analysis by reducing sample size.

It ensures equal representation of all individuals.

It helps to minimize sampling bias within specific subgroups. (correct)

In stratified sampling, what must be true about the strata?

Strata must be mutually exclusive classes. Signup and view all the answers

What is the final step in the stratified sampling process?

Combine the individual samples into one total sample. Signup and view all the answers

How does the size of the sample affect the magnitude of a statistical measure?

It decreases with the increase in sample size. Signup and view all the answers

In which scenario is the magnitude of a statistical measure likely to be smaller?

In homogeneous populations. Signup and view all the answers

What effect does population homogeneity have on statistical measures?

It often results in a smaller magnitude of the measure. Signup and view all the answers

Which of the following statements is true regarding sample size and statistical magnitude?

Statistical magnitude diminishes with larger sample sizes. Signup and view all the answers

Which factor is influential in determining the effect of sample size on statistical measures?

Population characteristics greatly influence measure magnitude. Signup and view all the answers

What do sampling errors represent in research?

Random variations in sample estimates Signup and view all the answers

How is the level of sampling error affected by sample size?

A smaller sample size increases sampling error Signup and view all the answers

Which statement about sampling errors is true?

They fluctuate randomly and are unavoidable Signup and view all the answers

What impact does increasing the sample size have on the accuracy of population estimates?

Increases the accuracy by reducing sampling error Signup and view all the answers

Which of the following can help control sampling errors?

Implementing random sampling techniques Signup and view all the answers

What is one factor that does not influence the determination of sample size?

Size of the research team Signup and view all the answers

What standard normal deviate is commonly used for a 95% confidence level in sample size calculations?

1.96 Signup and view all the answers

Which of the following factors affects the level of precision needed in sample size determination?

The variability of characteristics in the population Signup and view all the answers

What does the independent variable influence in an experiment?

It causes an increase or decrease in the dependent variable. Signup and view all the answers

In sample size calculation, what does the proportion in the target population refer to?

The likelihood of a certain characteristic present Signup and view all the answers

Which sampling technique might lead to different sample size requirements due to population heterogeneity?

Stratified sampling Signup and view all the answers

What is the purpose of a two-tailed hypothesis?

To test if there is a significant difference in both directions. Signup and view all the answers

What is often referred to as the Level of Significance in research?

The maximum error rate allowed by the researcher. Signup and view all the answers

At what common level is significance typically set by researchers?

0.05 (5%) Signup and view all the answers

What characterizes a one-tailed hypothesis?

It predicts a specific direction of the effect on the dependent variable. Signup and view all the answers

Study Notes

Stratified Samples

A population is divided into groups based on shared characteristics
A simple random sample is taken from each group
All of the samples are combined together into one group

Sampling Errors

They are the variability of sample estimates compared to real population parameters
The level of error depends on sample size
Larger sample size leads to smaller error
Smaller error is possible in homogeneous population

Determining Sample Size

Analyze the type of research to be conducted
Determine the level of precision needed
Consider the population's homogeneity or heterogeneity
Evaluate available resources
Consider the sampling technique used

Sample Size Calculation

The desired sample size is calculated based on factors including the standard normal deviate (usually set at 1.96 for 95% confidence level) and the proportion of the target population with a specific characteristic.

Hypotheses

Two-tailed hypothesis tests for increases or decreases in the dependent variable
One-tailed hypothesis tests for increases OR decreases in the dependent variable
The level of significance (alpha) is set by the researcher at the start, typically 0.05 (5%).
Confidence interval (C.I.) is a range within which the true population parameter is likely to lie.

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Description

Explore the concepts of stratified sampling, sampling errors, and sample size determination. This quiz delves into the methods of calculating sample size and understanding hypotheses in research. Test your knowledge on the importance of sample size in achieving reliable research outcomes.