Quantitative Lecture 7 Flashcards
What is a sample mean?
The mean of your sample, which is a subset of the population.
What is a population mean?
The mean in the entire population.
What factors affect the width of confidence intervals?
Variation and sample size.
How does variation affect confidence intervals?
Greater variation in the population leads to a greater confidence interval.
How does sample size affect confidence intervals?
Larger samples are more similar to each other, leading to narrower confidence intervals.
What is a point estimate?
A sample mean is known as a point estimate of the population mean.
What are confidence intervals?
Boundaries within which we think the population value will fall.
What is a bad example of a confidence interval?
A sample mean of 11.8 with a confidence interval of 0 to 30.
What is the standard error?
A measure of how accurately our data reflect the true population.
How is standard error calculated?
Standard error = SD / √sample size.
What is the formula for calculating the 95% confidence interval?
95% confidence interval = standard error * 1.96.
What is the standard error for the sample scores 9, 12, 13, 10, 12, 11, 13, 12, 13, 13?
Standard error = 1.33 / √10 = 0.42.
What is the 95% confidence interval for the sample mean of 11.8?
The confidence interval is 11.8 +/- 0.82, so it is 10.98 - 12.62.
What is a null hypothesis (H0)?
A hypothesis stating that there is no effect or relationship.
What is an alternative hypothesis (H1)?
A hypothesis stating that there is a difference or effect between variables.
What is a directional hypothesis?
A hypothesis that specifies the direction of the relationship or effect.
What is a non-directional hypothesis?
A hypothesis that does not specify the direction of the difference or effect.
What is the difference between one-tailed and two-tailed hypotheses?
One-tailed specifies direction; two-tailed does not.
What is the p-value in hypothesis testing?
The probability of obtaining the observed data if the null hypothesis is true.
What does a p-value less than 0.05 indicate?
Sufficient evidence to reject the null hypothesis.
What does statistical significance mean?
It indicates that the results are unlikely to have occurred by chance.
What is the central limit theorem?
As the sample size increases, the sample means will be closer to the population mean.
What is the importance of effect sizes?
They provide a more intuitive understanding of the significance of results.
