Modules Week 2

Question 1

What if we want to know if not just an individual, but a sample, was typical or if it was extreme?

Answer 1

Firstly, we would need a score for our one sample. This would be the sample mean. Next, we would need a distribution made up of sample means, within which, we could examine our one sample mean.

Question 2

What is a Distribution of Sample means?

Answer 2

A Distribution of Sample Means is made up of the sample means from all of the random samples of a certain size (n) that could possibly be obtained from a population.

Question 3

Distributions of Sample Means will have the ________ shape no matter what the original ________ was

Answer 3

same, skew

Question 4

What is the Distribution od Sample means governed by?

Answer 4

The Central Limit Theorem tells us the precise characteristics of the distribution of any distribution of sample means.

Question 5

What does the Central Limit Theorum tell us?

Answer 5

The precise characteristics of a distribution of sample means for samples of any size (n).

The mean of the distribution of sample means is the same as the population mean.

For large sample sizes (30 or more), the distribution of sample means will have a normal shape.

Question 6

What is Standard Error?

Answer 6

The standard deviation of the distribution of sample means, which is called “Standard Error”.

Question 7

What is the formula for Standard Error?

Answer 7

σM=σ/square root of n

= standard error = standard deviation of the population/ number of people in the sample

Question 8

As sample size ______, standard error ________. In turn, estimation of the mean becomes ______ _______.

Answer 8

increases, decreases, more precise (and can provide a reliable estimate of pop. mean)

Question 9

What does this all mean?

Answer 9

We know if our sample is large enough, the distribution of sample means will be normal.

We know the mean of the distribution of sample means, and we can calculate its standard error.

Therefore, we can use our 2s rule of thumb to test if our sample mean is typical or if it is extreme.

Question 10

What is a hypothesis?

Answer 10

A hypothesis is a predictive statement. When we conduct psychological research, we pose and test an experimental hypothesis (always predicts effect)

An experimental hypothesis is a statement that predicts an effect. This effect might be one of…

[Difference] or [Association]

Experimental hypotheses are also called alternative hypotheses. But, alternative to what?

Question 11

What is the Null Hypothesis?

Answer 11

A null hypothesis is also a prediction. The null always predicts the one basic concept regardless of what is being investigated – that nothing is happening. In other words, the null hypothesis is a hypothesis of no effect.

[No Difference] [No Association]

The experimental hypothesis is the alternative to the null hypothesis. Only one of these hypotheses can be supported by the research data.

Question 12

What is the statistical notation for the null hypothesis?

Answer 12

The null hypothesis is denoted as follows: H0

The alternative hypothesis is indicated by: H1

Question 13

How is Null Hypothesis Significance Testing conducted (4 steps)?

Answer 13

1. Propose a null hypothesis that a population parameter (mean) has a particular value.
2. Proceed assuming the null hypothesis is true.
3. Determine the probability of the sample mean occurring if the null hypothesis is true.
4. If the probability of the sample mean occurring is small, reject the null hypothesis. If the probability is large, do not reject the null hypothesis.

Question 14

When is a result statistically significant?

Answer 14

A result is consideredstatistically significantif the p value is below a predeterminedsignificance level (α), typically .05.

Question 15

What are Type 1 and Type 2 errors?

Answer 15

The chapter explains the concepts ofType I errors(rejecting a true H₀),Type II errors(failing to reject a false H₀), andstatistical power(the ability to detect an effect when it exists).