Chapter 9 Flashcards
(26 cards)
what is Z-Score Formula
A standardized score that indicates the location of a score within a population distribution
Why is a z-score transformation conducted
provides a way of locating a score in a standardized distribution.
When is a z-score transformation conducted
we want to compare two scores that come from two different populations.
The Formula for z score(equation)
Understand the z Score Distribution (look at Figure 9.3)
Z= x-u/o u = mean o= Standard deviation
Understanding how to use the unit normal table (z table)
WILL BE GIVEN TO US ON TEST
Remember: These flips when we have a negative z-value
what is the Standard Error Formula
S__ =s/Square root of N
x
How is standard error different from standard deviation?
HINT
Similarity(both measures of variability)
standard deviation reflects variability within a sample
standard error estimates the variability across samples of a population.
what is a One Sample z-Test
Significance test used to compare means
Five Steps in Hypothesis Testing
Step 1: State your research question and make hypotheses about the answer.
Step 2: Set a decision criterion for making a decision about the hypotheses.
Step 3: Collect your sample data.
Step 4: Calculate statistics.
Step 5: Make a decision about the hypotheses.
Step 1: State your research question and make hypotheses about the answer.
State the research question, and develop the null and alternative hypotheses using literature in the research area.
Step 2: Set a decision criterion for making a decision about the hypotheses.
Set the decision criterion alpha (α) as a probability that the sample mean is a score in the distribution of sample means;
consider how your alpha level will influence the chance of Type I and Type II errors in your test.
Step 3: Collect your sample data.
Design your study to test your hypotheses, recruit sample participants or subjects, and collect data on the dependent variables of interest.
Step 4: Calculate statistics.
Summarize data with descriptive statistics;
choose an appropriate inferential statistics test and calculate the inferential statistic and corresponding probability (p) value for that statistic
Step 5: Make a decision about the hypotheses.
Compare the statistic p value with α;
make a decision to either reject or retain the null hypothesis based on this comparison and then decide if you can accept the alternative hypothesis.
what is a Null Hypothesis
The hypothesis that an effect or relationship does not exist (or exists in the opposite direction of the alternative hypothesis) in the population
what is a Alternative or Scientific Hypothesis
The hypothesis that an effect or relationship exists (or exists in a specific direction) in the population
What is a One-tail hypothesis
Only one direction of an effect or relationship is predicted in the alternative hypothesis of the test
What is a two-tail hypothesis
Both directions of an effect or relationship are considered in the alternative hypothesis of the test
What is a Type I errors
An error made in a hypothesis test when the researcher rejects the null hypothesis when it is actually true
What is a Type II errors
An error made in a hypothesis test when the researcher fails to reject the null hypothesis when it is actually false
What is the Significant test
p value is less than or equal to the alpha level in an inferential test and the null hypothesis can be rejected
What is Power
The ability of a hypothesis test to detect an effect or relationship when one exists (equal to 1 minus the probability of a Type II error)
What is p value
Probability value associated with an inferential test that indicates the likelihood of obtaining the data in a study when the null hypothesis is true
What is alpha level
The probability level used by researchers to indicate the cutoff probability level (highest value) that allows them to reject the null hypothesis
