Psy 202

A researcher determines that students are active about 60 ± 12 (M ± SD) minutes per day. Assuming these data are normally distributed, what is the z score for students being active 48 minutes per week?

-1.0

In hypothesis testing, a researcher's decision

All of the above

Based on the effect size conventions, d = 0.60 is a

Medium size effect

Which proportion is largest in a z distribution

The proportion of area between z = +1 and z = −1.

A researcher selects two samples of 25 participants each. In the first sample the population mean was 32 and the variance was 8. In this second sample, the population mean was 4 and the variance was 8. Which sample will be associated with a larger standard error of the mean?

The standard error will be the same

The probability of committing a Type I error is stated by ________; the probability for committing a Type II error is stated by ________.

There is a 3% likelihood of obtaining the test statistic value, if the null were true.

The following samples were selected by two researchers. Which is associated with a smaller standard error of the mean? Researcher A: n = 25, μ = 5, σ = 7 Researcher B: n = 25, μ = 32, σ = 7

They both have the same standard error

Most behavioral phenomena are believed to approximate the normal distribution.

true

The mean, median, and mode are all located at the 50th percentile in a perfect normal distribution.

true

Which of the following is not one of the four steps to hypothesis testing?

Evaluate the plan

Z score

For a z score, the mean is always the reference point

A researcher selects a sample of 16 participants from a population with a variance of 4. What is the standard error of the mea

Less than 1 Standard deviation is the square root of variance

Increasing sample size will

`Increase the power of the decision

Z score

How far a score is from the mean; along the x-axis; rarely goes beyond a 3. A normal distribution has a mean of 0 and a standard deviation of 1.

A statistics instructor wants to measure the effectiveness of his teaching skills in a class of 81 students (N = 81). He selects students by waiting at the door to the classroom prior to his lecture and pulling aside every third student to give him or her a questionnaire.

No, because each student is not selected at random, and each student is not replaced before selecting another student.

If p is less than alpha...

reject the null hypothesis

A researcher selects a sample of 121 participants from a population with a mean of 32 and a standard deviation of 22. What is the standard error of the mean?

2.0

A researcher finds that the average preschool-aged child drinks two cups of milk per day. Assuming these data are normally distributed, the z score for the average cups per day in this example is

equal to 0

The mean of the sampling distribution of sample means is

equal to the population mean

A method for testing a claim or hypothesis about a parameter in a population, using data measured in a sample, is called

hypothesis testing

A counselor records the number of disagreements (per session) among couples during group counseling sessions. If the number of disagreements is distributed normally as 4.4 ± 0.4 (M ± SD) disagreements, then what proportion of couples disagree at least 4 times during each counseling session?

0.8413 1- Near the tail

A researcher reports the following result for a one-sample z test at a 0.05 level of significance: z = 1.88, p = 0.06 (d = 0.25). Is this result significant?

No, the decision to retain the null hypothesis

Two researchers select a sample for a population with a mean of 12.4 and a standard deviation of 9. Researcher A selects a sample of 30 participants. Researcher B selects a sample of 40 participants. Which sample is associated with a smaller standard error?

Researcher B's, because the sample size was larger.

What does the standard error measure?

Standard error measures the distance that sample mean values can be expected to deviate from the value of the population mean

A researcher conducts two studies. Each study was a one-sample z test. Both studies placed the rejection region in both tails and measured the same sample mean. The alpha level in Study 1 was larger than the alpha level used in Study 2. Which study is associated with greater power to detect an effect?

Study 1

Which of the following statements regarding the null hypothesis is true?

The null hypothesis always makes statements about a population parameter.

A sample mean is not always equal to a population mean.

True

A sampling distribution is a distribution of all sample means or sample variances that could be obtained in samples of a given size from the same population.

True

The null hypothesis and alternative hypotheses are statements about parameters in the population.

True

A distribution of all sample means or sample variances that could be obtained in samples of a given size from the same population is called

a sampling distribution

The probability of committing a Type I error is stated by ________; the probability for committing a Type II error is stated by ________.

alpha; beta