Chapter 7 post test

A researcher selects a sample of 284 participants from a population of college students. For his study, he determines that the population mean is 47 and has a standard deviation of 23. What is the standard error?

1.36

A research assistant is trying to find the total number of possible samples. He determines that the population (N = 5) while (n = 3). Using the experimental strategy of sampling, what number will the researcher assistant calculate?

10

A researcher finds that , what is the standard error of the mean?

14

A researcher determines the mean of his sampling distribution is M = 15. What is the population mean?

15

Looking at the table from Question 10, what is the mean of the sampling distribution of the sample variances ()?

3.23

Using the table below, what is the population variance (σ2)?

3.25

A principle of a local high school selects a sample of students from the population of high school students. He determined earlier that the shape of the distribution for the population was negatively skewed. If this is true, what can the principle expect the shape of the sampling distribution of sample variances to look like?

positively skewed

A researcher wants to randomly select participants to be assigned to different groups. To do this, he places the participants name in a hat, shakes it, and randomly selects a name. Afterward, he discards the name into the trash. This is an example of what sampling method?

sampling without replacement

A research assistant working under the researcher from Question 17 forgot to record the scores of six participants. He hopes his mistake will go unnoticed as he randomly selects six new participants from the normally distributed population; however before he can do this, what has happen to the standard error of the mean?

It increased

Due to the fact that the sum of squares is divided by the degrees of freedom, we know that the sample variance ______.

is an unbiased estimator of the population variance

A researcher chooses a sample of 32 participants from a normally distributed population however, she finds that she needs more samples to even out the number of people in each group. Therefore she randomly selects 4 more participants. Based on this example, what has happen to the standard error of the mean?

it decreased

A researcher randomly selects scores (n = 20) from a positively skewed distribution of a certain population. He then uses these scores to create a sampling distribution of sample means. From this information, what will be the shape of the sample distribution?

normally distributed

As the population standard deviation increases, the standard error decreases.

False

The best way to report the standard error of the mean is in a graph.

Fasle

A high school statistics teacher wants to know if students enjoy his class. Using a Likert-type scale (1-5), he first determines through his students that his sample mean M = 10 while the population mean μ = 30. What might be the reason M ≠ μ?

He did not select a random sample of students.

When reporting the standard error of the mean in a graph, verticle lines may represent the SEM.

True

When reporting the standard error of the mean in a table, it is displayed as M ± SEM.

True

While a sample distribution is the distribution of all sample means or sample variances, what scores are distributed on the x-axis for a sample distribution of the sample mean?

sample means

A researcher decides to try theoretical sampling in her next study. What type of sampling method will she use for her study?

sampling with replacement

A researcher randomly selects names from a hat from a participant pool made of 8 males and 22 females. He determines that the probability of selecting two male participants is p = .07. What type of sampling method did the researcher use based of the probability?

sampling with replacement