Mastery opportunity 2

z-scores

Transforming data to ____can be useful in cases where we want to compare two scores that come from two different populations

z score

z-Scores can help us test our hypotheses by determining the location of a mean in the distribution of sample means using a(n) _____ calculation

z-test

The z-score can be used in a one-sample ____as an inferential statistic that can help us test hypotheses

Z test

You will need to pay attention to the sign (+ or -) of the ____ when you decide which column of the table to use in determining the correct percentage for the score you are looking for.

Z-score

The sign of the Z-score (positive or negative) tells us whether the score is above or below the _____ mean.

population

In the following formula: Z=(X-u)/Q, we see that __ is the score we want to transform.

X

Using the z-score transformation ___ the scores according to the population they came from to allow us to compare the scores by giving us the location of the score in their distribution

Standardization

In a z-score distribution, the standard deviation of the Z-score will be ___.

+1

Knowing the percentage of scores in different portions of the ____ is useful because it can help us determine the likelihood of getting a specific range of scores in the distribution

normal distribution

A ____ is a value that represents the distance of a score from the population mean in terms of how many standard deviations the distance represents in that population.

Z Score

We can use the mean from the distribution of sample means along with its standard deviation to determine the current mean of a sample by using the samples___.

Z-score

This is the most extreme portion of a distribution of statistical values for the null hypothesis determined by the decision criterion.

critical region

This assumes that an effect or relationship does not exist in the population.

null hypothesis

A Type I error made in a hypothesis test occurs when the researcher accepts the null hypothesis when it is actually false.

True

Step 5 in the hypothesis testing procedure is ____.

make a decision about the hypothesis

The ____ our sample is, the closer we will get to the actual population values in our sample

larger

Standard deviation of the sample means is known as___?

standard error

IF our population is a normal distribution or our sample size is greater than 30, we use this to determine how extreme a score this is in the distribution of sample means

unit normal table

The starting place for our ____ procedure is a research question we want to answer.

hypothesis testing

The following: H1: In the general population, older individuals have lower memory scores than younger individuals, is an example of what type of alternative hypothesis?

one-tailed hypothesis

The___ associated with an inferential test that indicates the likelihood of obtaining the data in a study when the null hypothesis is true.

p Value

Step 4 in the hypothesis testing procedure is ___.

Calculate statistics

Step 2 in the hypothesis testing procedure is___.

Set a decision criterion for making a decision about the hypothesis

The ___ for the distribution of sample means will tell us the location of our sample mean within this distribution.

Z score

____ is calculated based on the distance of the score from the mean divided by the standard deviation of the distribution.

Z score

These scores are the sample means from all possible samples of specific size drawn at random from the population.

distribution of sample means

Even if we reject the null hypothesis as our decision in the test, there is still a small chance that it is true.

true

Assumption 1 of the t- test states that the population tsample is drawn from

There are two___ that a researcher must known to be true in order to use a t-test.

assumptions

Calculating an inferential statistic will provide the location of our___ in the population distribution of sample means for the null hypothesis

sample mean

In using t as an inferential statistic, we follow the same procedures as for the ___.

Z-test

____is the sample standard deviation divided by the square root of the sample size.

Estimated standard error

The one-tailed test has a(n)___ at one end of the t distribution that is twice the size of the two-tailed.

critical region

It is typical for behavioral research to use the alpha level at___.

.05

What is the Z-score for the following data?

X = 21.3

mean = 27.4

SD = 1.2

Make sure to round to 2 decimal places

We use the t Distribution Table to find out ___value.

t-critical

The independent samples t-test may consist of samples from a population exposed to different___.

Treatment conditions

An independent sample t-test is considered a between-subjects design because it involves the comparison to two___ and independent samples.

separate

The independent samples t-test may consist of samples drawn from___populations.

different

This provides us with the difference between sample means minus the expected population mean difference for the null hypothesis, divided by the estimated standard error.

Independent sample t-test

For a t-test difference to be considered significant the t-score for the sample must be within the critical regions of the___.

t distribution

This provides the sum of the sum of squares of each sample divided by the sum of the degrees of freedom for each sample.

pooled variance

This will serve as the estimate of sampling error in an independent samples t-test and is based on the variability from the two samples in the study.

pooled variance

A comparison of the p value to the ___helps us make the decision to accept or reject the null hypothesis.

Alpha (a) level

We use the t Distribution Table to find our ___value

tcrit

The independent samples t-test may consist of samples from a population exposed to different___

treatment conditions

An independent sample t-test is considered a between-subjects design because it involves the comparison of two___ and independent samples

separate

The independent samples t-test may consist of samples drawn from___ populations

different

This provides us with the difference between sample means minus the expected population mean difference for the null hypothesis, divided by the estimated standard error.

independent samples t-test

For a t-test difference to be considered significant the t score for the sample must be within the critical regions of the ___

t distribution

This provides the sum of the sum of squares of each sample divided by the sum of the degrees of freedom for each sample

pooled variance

This will serve as the estimate of sampling error in an independent samples t-test and is based on the variability from the two samples in the study.

pooled variance

A comparison of the p value to the ___ helps us make the decision to accept or reject the null hypothesis.

Alpha level

In a ___ design, participants are paired across the treatment conditions on some variable of interest

matched

In___ study, we are no longer comparing a single sample with a known population mean. Instead, we are collecting data twice.

within-subjects

A one-sample t-test involves the sample mean minus the population mean, divided by the___

estimated standard error

select all of the following that are assumptions of a Z-test

• Data are normally distributed

• Population mean is known

• Each data point is independent of all other data points

• Population standard deviation is known

Select all of the following that are assumptions of a one-sample t-test

• Each data point is independent of all other data points

• Data are normally distributed

If our sample t score falls in the critical region, we can reject the ____

null hypothesis

In the case of related samples, we would use the ___ between the pairs of scores for each match as our dependent variable and compare the difference score mean with the difference expected, if there is no difference

difference scores

Which kind of error happens when we reject the null hypothesis when it is actually true?

Type I

A type I error can occur when we wrongfully ____

reject the null hypothesis

___is a type of research design where behavior is measured both before and after a treatment or condition is implemented.

Pretest-Posttest design

Step 5 in the hypothesis testing procedure is ___.

Make a decision about the hypothesis

Select all of the following that are assumptions of a related/dependent t-test

• Difference score are normally distributed

• Difference scores are independent

Select all of the following that are assumptions of an independent samples t-test

• Data are normally distributed

• Population variances for each sample are equal

• Each data point is independent of all other data points

The difference scores minus the population mean fro difference score, divided by the estimated standard error called___

related/paired samples t test

When we subtract value of one variable from values of another variable so that we can have a single sample mean to compare with a population mean, we call the calculated score

the difference score.

With a hand-calculated t test, we must compare our sample t score with the ___ from the table to decide if we have evidence against our null hypothesis

t crit value