### Create a StudySoup account

#### Be part of our community, it's free to join!

Already have a StudySoup account? Login here

# Exam 2 Study Guide PSY 2110

Ohio

GPA 3.9

### View Full Document

## About this Document

## 32

## 0

## Popular in Statistics for Behavioral Sciences

## Popular in Psychology (PSYC)

This 3 page Study Guide was uploaded by Shannan Dillen on Saturday October 1, 2016. The Study Guide belongs to PSY 2110 at Ohio University taught by S. Tice-Alicke in Fall 2016. Since its upload, it has received 32 views. For similar materials see Statistics for Behavioral Sciences in Psychology (PSYC) at Ohio University.

## Similar to PSY 2110 at Ohio

## Reviews for Exam 2 Study Guide

### What is Karma?

#### Karma is the currency of StudySoup.

#### You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 10/01/16

Exam 2 Study Guide Probability Analytical View: an analysis of possible outcomes to define probability o Ex: A bag contains 1 black marble and 9 white marbles. What is the probability of drawing a black marble? P(A) = A / (A + B) if event could be A or B and all outcomes are equally likely o Reduce to decimal form – 4 decimal places Relative Frequency View: defines probability in terms of past performance/outcomes o Ex: Waiting for a bus and after many days of doing this you notice that 75/100 times the bus is late. P(bus late) = .75 Subjective View: not based on actual numbers or calculations; defined in terms of personal belief in an outcome’s likelihood o What you believe will happen o May not be accurate, but important because it influences behavior o Ex: weather, likelihood of rejection if we ask someone out, likelihood of being punished if committing a crime Independent Events – occurrence of one event has no effect on the probability of the occurrence of another event o Ex: dice rolls Mutually Exclusive Events – the occurrence of one event makes the occurrence of another event impossible o If it’s one, it can’t be the other o Ex: gender, days of the week Conditional Probability – probability that one event will occur, given that another event has occurred o One has to happen for the other to happen Hypothesis Testing 5 Steps: State the hypothesis o Hypothesis – statement about the population parameter of sample data Null hypothesis – always states there is no difference; things are the same o HO Alternate Hypothesis (Research Hypothesis) – opposite of the null; there is a difference o H1 Set up criteria for making decision about the null o Draw graph – is it one-tailed or two-tailed? One-tailed: one region of rejection, p stays on one side Directional – specific direction prediction made Two-tailed: two regions of rejection, split p in half Non-directional – no specific direction prediction made CV – critical value – mark off the region of rejection o Find Z-scores from table based on regions of rejection Analyze the data o Sampling Distribution of the Means σ”xbar”Standard Error of the Mean (same thing conceptually as standard deviation) equals σ / √n Z = (???? - µ) / (σ/√n) Make decision about the null o Compare the computed value that you got from step 3, to the critical values form step 2 If in region of rejection, then reject the null If not in region of rejection, then retain the null/fail to reject the null Write conclusion o Ex: null was rejected There is a significant difference in the mean IQ with the IQ pill compared to the IQ without the IQ pill. o Ex: null was retained There is no significant difference in the mean IQ with the IQ pill compared to the IQ without the IQ pill. o Identify independent and dependent variables o Significant – statistical test has been performed and using probability, there is a difference Nothing to do with size of difference Sampling Distribution of Means – the distribution of all possible random sample means when an infinite number of random samples of the same size are randomly selected Central Limit Theorem – defines 3 properties of Sampling Distribution of Means (SDM) o Regardless of the shape of the raw score distribution, the SDM is nearly a normal distribution. o The mean of the SDM is always equal to the mean of the raw score population. o There is a mathematical relationship between variables of the raw scores and variability of sample means. Independent Samples t-test Use t-test when sigma is unknown df – degrees of freedom – the number of components in a calculation that are free to vary o df = n – 1 Test is used to determine if there is a significant difference between the population means of 2 random independent samples o All about differences between 2 groups Assumptions: o Populations from which the samples are drawn are normally distributed. o Homogeneity of Variance: σ1= σ 22 Two population variances are equal If one sample variance is no more than 4 times the other sample variance and the sample sizes are roughly equal, then good to go; not violation the assumption o The observations in each sample are independent. 2 2 If n’s are equal: √(S 1n +1S /n2) 2 If n’s are unequal: √(S /p + 1 /n p 2 o S p pooled variance = ((n – 1)1S ) + 1n – 1)(2 )) / (2 + n )1– 2 2 Confidence Intervals – range of values that we are confident contains the population parameter ̅ o CI .95 or .99 ± (tCV(S ”x bar” Always use the t critical value from a two-tailed test o Conclusion Example: We are 95% confident the population mean short term memory for students at Memoryville College falls in the interval 8.98 to 11.02.

### BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.

### You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

## Why people love StudySoup

#### "I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

#### "I made $350 in just two days after posting my first study guide."

#### "There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

#### "It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

### Refund Policy

#### STUDYSOUP CANCELLATION POLICY

All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email support@studysoup.com

#### STUDYSOUP REFUND POLICY

StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here: support@studysoup.com

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to support@studysoup.com

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.