A school psychologist is interested in determining if children with attention deficit hyperactivity disorder (ADHD) learn better if English literature is read to them rather than having them read the material alone by themselves. A random sample of 10 sixth graders with ADHD is selected and divided into two groups of n=9. One of the groups has a story read to them (Listening Group) and the other reads the story alone by themselves (Reading Group). A test on the story is given after each group has finished reading or hearing the story. The following scores were obtained with 20 being a perfect score. what is the cohen’s d ?

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
icon
Related questions
Question
A school psychologist is interested in determining if children with attention deficit hyperactivity disorder (ADHD) learn better if English literature is read to them rather than having them read the material alone by themselves. A random sample of 10 sixth graders with ADHD is selected and divided into two groups of n=9. One of the groups has a story read to them (Listening Group) and the other reads the story alone by themselves (Reading Group). A test on the story is given after each group has finished reading or hearing the story. The following scores were obtained with 20 being a perfect score. what is the cohen’s d ?
### Two-Sample t-Test for Independent Groups

#### Groups and Raw Data
1. **Reading Group Scores:**
   - 10
   - 10
   - 7
   - 12
   - 8
   - 8
   - 10
   - 9
   - 11

2. **Listening Group Scores:**
   - 15
   - 12
   - 13
   - 11
   - 10
   - 9
   - 11
   - 10
   - 11

#### Statistical Analysis

| Statistic      | Reading Group | Listening Group |
|----------------|---------------|-----------------|
| Count (n)      |               |                 |
| Mean           |               |                 |
| DEVSQ (SS)     |               |                 |
| STDEV.S        |               |                 |
| df             |               |                 |
| \( S_{(M1-M2)} \) |           |                 |
| alpha          |               |                 |
| \( t_{crit} \) |               |                 |
| \( t_{obs} \)  |               |                 |
| Cohen's d      |               |                 |
| \( r^2 \)      |               |                 |

#### Decision
- **Reject Ho** 
- **Fail to reject Ho**

### Description of Data

The table presents results from a two-sample t-test comparing the means of two independent groups: a Reading Group and a Listening Group. Each group's scores on some measure are listed, and summary statistics for each group, including mean, deviation squared (DEVSQ or SS), standard deviation (STDEV.S), degrees of freedom (df), and the pooled standard error of the difference between means (\( S_{(M1-M2)} \)) are calculated.

The table also displays the alpha level (the probability of a Type I error), the critical t-value (\( t_{crit} \)), the observed t-value (\( t_{obs} \)), Cohen's d (a measure of effect size), and the coefficient of determination (\( r^2 \)).

The decision section indicates whether the null hypothesis (Ho) is rejected or not based on the t-test results.
Transcribed Image Text:### Two-Sample t-Test for Independent Groups #### Groups and Raw Data 1. **Reading Group Scores:** - 10 - 10 - 7 - 12 - 8 - 8 - 10 - 9 - 11 2. **Listening Group Scores:** - 15 - 12 - 13 - 11 - 10 - 9 - 11 - 10 - 11 #### Statistical Analysis | Statistic | Reading Group | Listening Group | |----------------|---------------|-----------------| | Count (n) | | | | Mean | | | | DEVSQ (SS) | | | | STDEV.S | | | | df | | | | \( S_{(M1-M2)} \) | | | | alpha | | | | \( t_{crit} \) | | | | \( t_{obs} \) | | | | Cohen's d | | | | \( r^2 \) | | | #### Decision - **Reject Ho** - **Fail to reject Ho** ### Description of Data The table presents results from a two-sample t-test comparing the means of two independent groups: a Reading Group and a Listening Group. Each group's scores on some measure are listed, and summary statistics for each group, including mean, deviation squared (DEVSQ or SS), standard deviation (STDEV.S), degrees of freedom (df), and the pooled standard error of the difference between means (\( S_{(M1-M2)} \)) are calculated. The table also displays the alpha level (the probability of a Type I error), the critical t-value (\( t_{crit} \)), the observed t-value (\( t_{obs} \)), Cohen's d (a measure of effect size), and the coefficient of determination (\( r^2 \)). The decision section indicates whether the null hypothesis (Ho) is rejected or not based on the t-test results.
### t-Test: Two-Sample Assuming Equal Variances

This section describes the results of a t-test conducted to compare the means of two independent groups, G1 and G2, under the assumption that their variances are equal.

**Group Statistics:**
- **G1:**
  - Mean: 8.77777778
  - Variance: 3.94444444
  - Observations: 9
- **G2:**
  - Mean: 11.4444444
  - Variance: 3.27777778
  - Observations: 9

**Pooled Variance:** 3.61111111

**Hypothesized Mean Difference:** 0

**Degrees of Freedom (df):** 16

**t-Test Calculations:**
- **t Stat:** -2.97683363
- **P(T<=t) one-tail:** 0.004449553
- **t Critical one-tail:** 1.745883676
- **P(T<=t) two-tail:** 0.008899105
- **t Critical two-tail:** 2.119905299

**Interpretation:**
The t-test statistical outputs provide essential information to determine if there is a statistically significant difference between the means of G1 and G2. 

- **Mean and Variance:** Shows the central tendency and spread of the data points within each group.
- **Pooled Variance:** A weighted average of the variances from both groups, used in the t-test calculation.
- **Hypothesized Mean Difference:** Typically set to 0 which uses the null hypothesis that there is no difference between the means.
- **Degrees of Freedom:** Reflects the number of values in the final calculation of a statistic that are free to vary.
- **t Stat:** The calculated t-statistic value from the test.
- **P-Values:** Indicates the probability of observing the test results under the null hypothesis. A lower value (typically less than 0.05) suggests rejecting the null hypothesis.
- **Critical Values:** These are the thresholds at which the null hypothesis would be rejected for one-tail and two-tail tests, respectively.

This t-test provides a detailed statistical analysis to help determine if the observed differences in group means are likely to be present in the population from which the samples were drawn.
Transcribed Image Text:### t-Test: Two-Sample Assuming Equal Variances This section describes the results of a t-test conducted to compare the means of two independent groups, G1 and G2, under the assumption that their variances are equal. **Group Statistics:** - **G1:** - Mean: 8.77777778 - Variance: 3.94444444 - Observations: 9 - **G2:** - Mean: 11.4444444 - Variance: 3.27777778 - Observations: 9 **Pooled Variance:** 3.61111111 **Hypothesized Mean Difference:** 0 **Degrees of Freedom (df):** 16 **t-Test Calculations:** - **t Stat:** -2.97683363 - **P(T<=t) one-tail:** 0.004449553 - **t Critical one-tail:** 1.745883676 - **P(T<=t) two-tail:** 0.008899105 - **t Critical two-tail:** 2.119905299 **Interpretation:** The t-test statistical outputs provide essential information to determine if there is a statistically significant difference between the means of G1 and G2. - **Mean and Variance:** Shows the central tendency and spread of the data points within each group. - **Pooled Variance:** A weighted average of the variances from both groups, used in the t-test calculation. - **Hypothesized Mean Difference:** Typically set to 0 which uses the null hypothesis that there is no difference between the means. - **Degrees of Freedom:** Reflects the number of values in the final calculation of a statistic that are free to vary. - **t Stat:** The calculated t-statistic value from the test. - **P-Values:** Indicates the probability of observing the test results under the null hypothesis. A lower value (typically less than 0.05) suggests rejecting the null hypothesis. - **Critical Values:** These are the thresholds at which the null hypothesis would be rejected for one-tail and two-tail tests, respectively. This t-test provides a detailed statistical analysis to help determine if the observed differences in group means are likely to be present in the population from which the samples were drawn.
Expert Solution
steps

Step by step

Solved in 2 steps with 2 images

Blurred answer
Knowledge Booster
Point Estimation, Limit Theorems, Approximations, and Bounds
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc
Probability and Statistics for Engineering and th…
Probability and Statistics for Engineering and th…
Statistics
ISBN:
9781305251809
Author:
Jay L. Devore
Publisher:
Cengage Learning
Statistics for The Behavioral Sciences (MindTap C…
Statistics for The Behavioral Sciences (MindTap C…
Statistics
ISBN:
9781305504912
Author:
Frederick J Gravetter, Larry B. Wallnau
Publisher:
Cengage Learning
Elementary Statistics: Picturing the World (7th E…
Elementary Statistics: Picturing the World (7th E…
Statistics
ISBN:
9780134683416
Author:
Ron Larson, Betsy Farber
Publisher:
PEARSON
The Basic Practice of Statistics
The Basic Practice of Statistics
Statistics
ISBN:
9781319042578
Author:
David S. Moore, William I. Notz, Michael A. Fligner
Publisher:
W. H. Freeman
Introduction to the Practice of Statistics
Introduction to the Practice of Statistics
Statistics
ISBN:
9781319013387
Author:
David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:
W. H. Freeman