Capella FlexPath BS Psychology Class Samples:

FPX 4700

- PSYC FPX 4700 Assessment 5 – Data Analysis Worksheet – Correlations
- PSYC FPX 4700 Assessment 4 – ANOVA, Chi-Square Tests, and Regression
- PSYC FPX 4700 Assessment 3 – Hypothesis, Effect Size, Power, and t Tests
- PSYC FPX 4700 Assessment 2 Central Tendency and Probability
- PSYC FPX 4700 Assessment 1 Basics of Research and Statistics, Frequency Distributions, Percentiles, and Graphical Representations

FPX 1000

FPX 2300

FPX 4300

FPX 3002

FPX 2800

# PSYC FPX 4700 Assessment 3 – Hypothesis, Effect Size, Power, and t Tests

## Capella 4700 Assessment 3

**Assessment 3 – Hypothesis, Effect Size, Power, and t Tests**

**Assessment 3 – Hypothesis, Effect Size, Power, and t Tests**

Name:

Capella University

## PSYC-FPX 4700 Assessment 3:

## Statistics for the Behavioral Sciences

Prof. Name:

Date

**Assessment 3 – Hypothesis, Effect Size, Power, and ***t ***Tests**

*t*

Complete the following problems within this Word document. Do not submit other files. Show your work for problem sets that require calculations. Ensure that your answer to each problem is clearly visible. You may want to highlight your answer or use a different type color to set it apart.

**Hypothesis, Effect Size, and Power**

**Problem Set 3.1: ****Sampling Distribution of the Mean Exercise**

**Criterion:** Interpret population mean and variance.

**Instructions:** Read the information below and answer the questions.

Suppose a researcher wants to learn more about the mean attention span of individuals in some hypothetical population. The researcher cites that the attention span (the time in minutes attending to some task) in this population is normally distributed with the following characteristics: 20 36 . Based on the parameters given in this example, answer the following questions:

#### What is the population mean (μ)? __________________________

#### What is the population variance ?

#### Sketch the distribution of this population. Make sure you draw the shape of the distribution and label the mean plus and minus three standard deviations.

**Problem Set 3.2:**** Effect Size and Power**

**Criterion:** Explain effect size and power.

**Instructions:** Read each of the following three scenarios and answer the questions.

Two researchers make a test concerning the effectiveness of a drug use treatment. Researcher A determines that the effect size in the population of males is *d* = 0.36; Researcher B determines that the effect size in the population of females is *d* = 0.20. All other things being equal, which researcher has more power to detect an effect? Explain. ______________________________________________________________________

Two researchers make a test concerning the levels of marital satisfaction among military families. Researcher A collects a sample of 22 married couples (*n* = 22); Researcher B collects a sample of 40 married couples (*n* = 40). All other things being equal, which researcher has more power to detect an effect? Explain. ______________________________________________________________________

Two researchers make a test concerning standardized exam performance among senior high school students in one of two local communities. Researcher A tests performance from the population in the northern community, where the standard deviation of test scores is 110 (); Researcher B tests performance from the population in the southern community, where the standard deviation of test scores is 60 (). All other things being equal, which researcher has more power to detect an effect? Explain. ______________________________________________________________________

**Problem Set 3.3:**** Hypothesis, Direction, and Population Mean**

**Criterion:** Explain the relationship between hypothesis, tests, and population mean.

**Instructions:** Read the following and answer the questions.

Directional versus nondirectional hypothesis testing. Cho and Abe (2013) provided a commentary on the appropriate use of one-tailed and two-tailed tests in behavioral research. In their discussion, they outlined the following hypothetical null and alternative hypotheses to test a research hypothesis that males self-disclose more than females:

- H0: µmales − µfemales ≤ 0
- H1: µmales − µfemales > 0

- What type of test is set up with these hypotheses, a directional test or a nondirectional test? ____________________________________________________
- Do these hypotheses encompass all possibilities for the population mean? Explain. ____________________________________________________

**Problem Set 3.4:**** Hypothesis, Direction, and Population Mean**

**Criterion:** Explain decisions for p values.

**Instructions:** Read the following and respond to the prompt.

The value of a p value. In a critical commentary on the use of significance testing, Lambdin (2012) explained, “If a p < .05 result is ‘significant,’ then a p = .067 result is not ‘marginally significant’” (p. 76).

Explain what the author is referring to in terms of the two decisions that a researcher can make. _________________________________________________

*t-Tests*

**Problem Set 3.5: ****One-Sample ***t ***test in JASP**

*t*

**Criterion:** Calculate a one-sample *t* test in JASP.

**Data: **Use the dataset minutesreading.jasp. The dataset minutesreading.jasp is a sample of the reading times of Riverbend City online news readers (in minutes). Riverbend City online news advertises that it is read longer than the national news. The mean for national news is 8 minutes per week.

**Instructions:** Complete the steps below.

- Download minutesreading.jasp. Double-click the icon to open the dataset in JASP.
- In the
**Toolbar**, click**T-tests.**In the menu that appears, under**Classical,**select**One-sample t-test.** - Select
**Time**and then click**Arrow**to send it over to the Variables box. - Make sure the box is checked for
**Student.**In the box labeled**Test value**, enter**8**. Hit enter. - Copy and paste the output into the Word document.
- State the nondirectional hypothesis.
- State the critical
*t*for*a = .05*(two tails). - Answer the following: Is the length of viewing for Riverbend City online news significantly different than the population mean? Explain.

**Note**: **You will continue to use this dataset for the next problem.**

**Problem Set 3.6: ****Confidence Intervals**

**Criterion:** Calculate confidence intervals using JASP.

**Data: **Continue to use the dataset minutesreading.jasp.

**Instructions:** Based on the output from Problem Set 6.2, including a test value (population mean) of 8, calculate the 95% confidence interval by following the steps below.

- Check the box
**Location Estimate**. - Check the box
**Confidence interval**. Fill in the box with**95.0**%. - Copy and paste the output into the Word document.

**Problem Set 3.7:**** Independent Samples ***t*** Test**

*t*

**Criterion:** Calculate an independent samples* t* test in JASP.

**Data: **Use the dataset scores.jasp. Dr. Z is interested in discovering if there is a difference in depression scores between those who do not watch or read the news and those who continue with therapy as normal. She divides her clients with depression into 2 groups. She asks Group 1 not to watch or read any news for two weeks while in therapy and asks Group 2 to continue with therapy as normal. The dataset scores.jasp is a record of the results of the measure, administered after 2 weeks.

**Instructions:** Complete the steps below.

- Download scores.jasp. Double-click the icon to open the dataset in JASP.
- In the
**Toolbar**, click**T-tests.**In the menu that appears, under**Classical,**select**Independent-samples T-test.** - Select
**Score**and then click the top**Arrow**to send it over to the**Dependent Variables**box. - Select
**Group**and then click the bottom**Arrow**to send it over to the**Grouping Variable**box. - Make sure the
**Student**box is selected. Also select**Descriptives**and deselect any other boxes. - Copy and paste the output into the Word document.

**Problem Set 3.8: ****Independent ***t*** Test in JASP**

*t*

**Criterion:** Identify IV, DV, and hypotheses and evaluate the null hypothesis for an independent samples *t* test.

**Data: **Use the information from Problem Set 3.7.

**Instructions:** Complete the following:

- Identify the IV and DV in the study. _____________________________________
- State the null hypothesis and the directional (one-tailed) alternative hypothesis. ___________________________________________________
- Can you reject the null hypothesis at α = .05? Explain why or why not. ___________________________________________________

**Problem Set 3.9: ****Independent ***t*** Test using Excel**

*t*

**Criterion:** Calculate an independent samples* t* test in Excel.

**Data:** Use this data:

Depression Scores:

Group 1: 34, 25, 4, 64, 14, 49, 54

Group 2: 24, 78, 59, 68, 84, 79, 57

**Instructions:** Complete the following steps:

- Open
**Excel**. - On an empty tab, enter the data from above. Use
**column A**for**group 1**and**column B**for**Group 2**. In**Cell A1**, enter 1. In**cell B1**, enter 2. - Enter the data for each group below the label.
- Click
**Data Analysis**, select**t-Test: Two-Sample Assuming Equal Variances**. Click**OK.** - In
**Variable 1 Range**enter**$A$2:$A$8.**(Or, click the graph icon at the right of the box and highlight your data for Group 1. Then, click the graph icon.) - In
**Variable 2 Range**enter**$B$2:$B$8.** - Then click
**OK**. Your results will appear on a**new tab**to the left. - Return to your data. Click
**Data Analysis,**select**t-Test: Two-Sample Assuming Unequal Variances**. Then click**OK.** - In
**Variable 1 Range**enter**$A$2:$A$8.**(Or, click the graph icon at the right of the box and highlight your data for Group 1. Then, click the graph icon.) - In
**Variable 2 Range**enter**$B$2:$B$8.** - Then click
**OK**. Your results will appear on a**new tab**to the left. - Copy the results from both
*t*tests below.