Quantitative Lecture 7

Question 1

What is a sample mean?

Answer 1

The mean of your sample, which is a subset of the population.

Question 2

What is a population mean?

Answer 2

The mean in the entire population.

Question 3

What factors affect the width of confidence intervals?

Answer 3

Variation and sample size.

Question 4

How does variation affect confidence intervals?

Answer 4

Greater variation in the population leads to a greater confidence interval.

Question 5

How does sample size affect confidence intervals?

Answer 5

Larger samples are more similar to each other, leading to narrower confidence intervals.

Question 6

What is a point estimate?

Answer 6

A sample mean is known as a point estimate of the population mean.

Question 7

What are confidence intervals?

Answer 7

Boundaries within which we think the population value will fall.

Question 8

What is a bad example of a confidence interval?

Answer 8

A sample mean of 11.8 with a confidence interval of 0 to 30.

Question 9

What is the standard error?

Answer 9

A measure of how accurately our data reflect the true population.

Question 10

How is standard error calculated?

Answer 10

Standard error = SD / √sample size.

Question 11

What is the formula for calculating the 95% confidence interval?

Answer 11

95% confidence interval = standard error * 1.96.

Question 12

What is the standard error for the sample scores 9, 12, 13, 10, 12, 11, 13, 12, 13, 13?

Answer 12

Standard error = 1.33 / √10 = 0.42.

Question 13

What is the 95% confidence interval for the sample mean of 11.8?

Answer 13

The confidence interval is 11.8 +/- 0.82, so it is 10.98 - 12.62.

Question 14

What is a null hypothesis (H0)?

Answer 14

A hypothesis stating that there is no effect or relationship.

Question 15

What is an alternative hypothesis (H1)?

Answer 15

A hypothesis stating that there is a difference or effect between variables.

Question 16

What is a directional hypothesis?

Answer 16

A hypothesis that specifies the direction of the relationship or effect.

Question 17

What is a non-directional hypothesis?

Answer 17

A hypothesis that does not specify the direction of the difference or effect.

Question 18

What is the difference between one-tailed and two-tailed hypotheses?

Answer 18

One-tailed specifies direction; two-tailed does not.

Question 19

What is the p-value in hypothesis testing?

Answer 19

The probability of obtaining the observed data if the null hypothesis is true.

Question 20

What does a p-value less than 0.05 indicate?

Answer 20

Sufficient evidence to reject the null hypothesis.

Question 21

What does statistical significance mean?

Answer 21

It indicates that the results are unlikely to have occurred by chance.

Question 22

What is the central limit theorem?

Answer 22

As the sample size increases, the sample means will be closer to the population mean.

Question 23

What is the importance of effect sizes?

Answer 23

They provide a more intuitive understanding of the significance of results.