Research final

____________ is usually set at 4 X alpha (4X 0.05 = .20) •If alpha is 0.05, then •Power = 1-4(alpha) •That is 1-.20 = .80 •That means there is a probability of 80% chance of detecting a relationship

1-B Beta

The number of individuals in your sample depends on the size of the population, and on how precisely you want the results to represent the population as a whole.

Sample size You can use a sample size calculator to determine how big your sample should be. In general, the larger the sample size, the more accurately and confidently you can make inferences about the whole population.

Take participant score and subtract from mean and then divide by standard deviation. if a person makes an 80 on test and mean is 90 then that is -10 divided by 5 so -2

Z score To get the T score you would multiply the Z score by 10 and then add 50 so -2(10) = -20 -20 +50 = 30

Probability sampling methods In a ______________________, individuals are selected based on non-random criteria, and not every individual has a chance of being included. This type of sample is easier and cheaper to access, but it has a higher risk of sampling bias, and you can't use it to make valid statistical inferences about the whole population. ______________________ techniques are often appropriate for exploratory and qualitative research. In these types of research, the aim is not to test a hypothesis about a broad population, but to develop an initial understanding of a small or under-researched population.

non-probability sample Four types 1. Convenience sampling 2. Voluntary response sampling 3. Purposive sampling 4. Snowball sampling

6 rosc and 2 without in HIO group 6/2 2 rosc and 6 without in control 2/6 cross multiply 6*6 = 36 2*2= 4 36/4 = 9 therefore you are 9 times more likely to have rosc with HIO

odds ratio

The ___________________ is the entire group that you want to draw conclusions about.

population The population can be defined in terms of geographical location, age, income, and many other characteristics

The ________________, or factor analysis, compares the mean differences between groups that have been split on two independent variables (called factors). The primary purpose is to understand if there is an interaction between the two independent variables on the dependent variable

two-way ANOVA (factoral ANOVA)

Regression how to calculate predicted score.

use the values in the "B" column under the "Unstandardized Coefficients" column, as shown below: to present the regression equation as: Price = 8287 + 0.564 (Income) so if someone makes $100,000 he would typically pay? 100,000 (.564) + 8287= 64,687 50,000 (.56) + 8287=

Non-probability sampling methods Similar to a convenience sample, a ______________________ is mainly based on ease of access. Instead of the researcher choosing participants and directly contacting them, people volunteer themselves (e.g. by responding to a public online survey). Voluntary response samples are always at least somewhat biased, as some people will inherently be more likely to volunteer than others.

voluntary response sample Example You send out the survey to all students at your university and a lot of students decide to complete it. This can certainly give you some insight into the topic, but the people who responded are more likely to be those who have strong opinions about the student support services, so you can't be sure that their opinions are representative of all students.

•This is significance also known as p. or probability of making type 1 error •Output data, any number less than 0.05 is significant; any number greater is no significance.

•Alpha is usually set at 0.05 by convention. May be set at 0.01 also by convention. •Selection of alpha before study starts

________________________________________ (covariance adjust for a variant) can be thought of as an extension of the one-way ANOVA to incorporate a covariate. 2. Like the one-way ANOVA, the ________________________________ is used to determine whether there are any significant differences between two or more independent (unrelated) groups on a dependent variable. 3. ANOVA looks for differences in the group means, the ______________ looks for differences in adjusted means (i.e., adjusted for the covariate). **** EXAMPLE You want to determine and compare the effectiveness of lecture, CD ROM, or use of human patient simulator on performance. RUN ANOVA to begin with to determine if difference on pretest. If so, use pretest as a covariate (spss will adjust)

1. The one-way ANCOVA (analysis of covariance) ANCOVA has the additional benefit of allowing you to "statistically control" for a third variable (sometimes known as a "confounding variable"), which you believe will affect your results. This third variable that could be confounding your results is called the covariate and you include it in your one-way ANCOVA analysis. General Linear Model > Univariate

Take truth and subtract the new instrument finding and then divide by the truth what is this for?

Accuracy blood sugar lab shows 100 the new instrument shows 90. 90-100 is 10. 10 is then divided by 100 giving 0.1 or 10%. Since the new instrument was off by 10% it suggests that the new instrument has a 90% accuracy.

Probability sampling methods _____________________, involves dividing the population into subgroups, but each subgroup should have similar characteristics to the whole sample. Instead of sampling individuals from each subgroup, you randomly select entire subgroups. If it is practically possible, you might include every individual from each sampled cluster. If the clusters themselves are large, you can also sample individuals from within each cluster using one of the other techniques. This method is good for dealing with large and dispersed populations, but there is more risk of error in the sample, as there could be substantial differences between clusters. It's difficult to guarantee that the sampled clusters are really representative of the whole population.

Cluster sampling Example The company has offices in 10 cities across the country (all with roughly the same number of employees in similar roles). You don't have the capacity to travel to every office to collect your data, so you use random sampling to select 3 offices - these are your clusters.

__________________ is based on the extent to which a measurement reflects the specific intended domain of content Example: develop criteria for intubation and airway management How to figure this out?

Content Validity Divide agreement by total number of agreement+disagreement example 5 agree and 5 disagree 5/10 = 0.5 or 50% does not equat the minimum which is 80% or what you would shoot for for a good instrument which is 90-100%

1. After criteria developed (go to literature to develop), give to uneven number of experts and anchor each criterion with Very Relevant, Relevant, Not Very Relevant, Not at All Relevant. Summarize into agree and disagree relative to relevancy. (combine first two and combine second two) 2. Revise instrument. Divide agreement by total number of agreements + disagreements—get percent agreement. 3. Ask if experts agree with answer if multiple-choice questions; ask if other questions need to be asked. 4. Need minimum of 80% agreement. Good instruments have 90% - 100% agreement

Content validity

______________________ statistical index of the degree to which two variables are associated, or related. We can determine whether one variable is related to another by seeing whether scores on the two variables covary---whether they vary together.

Correlation coefficient Co-relation -The relationship between two variables -Measured with a correlation coefficient -Most popularly seen correlation coefficient: Pearson Product-Moment Correlation

This is a variation of ANOVA. This allows the investigators to examine multiple dependent variables simultaneously. Recall that the independent variable is what the investigator is studying and the dependent variable is the outcome. Multiple dependent variables that are related to each other. Each dependent variable should be normally distributed Each dependent variable should be at interval or ratio level

Multiple Analysis of Variance (MANOVA) Multivariate Analysis 1. Examine multivariate tests—Most common is Wilks' Lambda. If 0.05 or less is terms of sig, then there is significance. 2. Run Post hoc to determine where the significance lies.

________________ Enters all dependent variables into model. Want to predict weight of individual. Have factors of blood type, height, shoe size, and weight of a group.

Multiple Regression

__________________________—two or more independent variable. Caution? The caution is you have to have large number. 1. 2 or more independent variables this is the key. 2. Run main effects for each independent variable. 3. Run interaction between independent variables. One may influence outcome or dependent variable whereas main effects may not be significant. E.g. drug is more effective for this ethnic group but not that one.

Factorial ANOVA (two way anova)

you could use _____________________ to understand whether exam performance can be predicted based on study time; whether cigarette consumption can be predicted based on smoking duration; and so forth. It is used when we want to predict the value of a variable based on the value of another variable.

Linear regression Analyze > Regression > Linear

•Ability of a statistical test to detect a relationship if one exists •Answers question, "If a sample value for a characteristic is different from the population value, what probability would I like to assign for detecting difference or relationship?"

Power 1-4(alpha) so if alpha is 0.05 1-4(0.05) 1-.20 = .80 •That means there is a probability of 80% chance of detecting a relationship

To draw valid conclusions from your results, you have to carefully decide how you will select a sample that is representative of the group as a whole. There are two types of sampling methods 1._____________________ involves random selection, allowing you to make statistical inferences about the whole group. 2. ____________________ involves non-random selection based on convenience or other criteria, allowing you to easily collect initial data.

Probability sampling Non-probability sampling

Non-probability sampling methods _______________________ involves the researcher using their judgement to select a sample that is most useful to the purposes of the research. It is often used in qualitative research, where the researcher wants to gain detailed knowledge about a specific phenomenon rather than make statistical inferences. An effective purposive sample must have clear criteria and rationale for inclusion.

Purposive Sampling Example You want to know more about the opinions and experiences of disabled students at your university, so you purposefully select a number of students with different support needs in order to gather a varied range of data on their experiences with student services.

flu shot group 3000 get flu of 103000 who received shot 3000/103000 non-flu shot group 86000 of 96000 got the flu 86000/96000

Relative Risk 3000/103000 = 0.029 86000/96000 = 0.9 0.9/0.029 = 31

1. ___________________ can show if there is a significant difference in time. Can have one variable and more than one variable over time. Can be used with pretest/posttest design where you may want to see effect over time with one independent variable. 2. Can have two or more independent variables and compare the groups by time and by groups. Output will tell you o If there are differences by group o If there are differences in time by group o If there are interactions You may show all groups are effective over time. Time will be compared but by group.

Repeated ANOVA Repeative anova (ranova) tells us if there is a difference in group over time. Analyze > General Linear Model > Repeated Measures

The ___________________is the actual list of individuals that the sample will be drawn from. Ideally, it should include the entire target population (and nobody who is not part of that population).

Sampling frame Example You are doing research on working conditions at Company X. Your population is all 1000 employees of the company. Your sampling frame is the company's HR database which lists the names and contact details of every employee.

Probability sampling methods ___________________ involves dividing the population into subpopulations that may differ in important ways. It allows you draw more precise conclusions by ensuring that every subgroup is properly represented in the sample. To use this sampling method, you divide the population into subgroups (called strata) based on the relevant characteristic (e.g. gender, age range, income bracket, job role). Based on the overall proportions of the population, you calculate how many people should be sampled from each subgroup. Then you use random or systematic sampling to select a sample from each subgroup.

Stratified sampling Example The company has 800 female employees and 200 male employees. You want to ensure that the sample reflects the gender balance of the company, so you sort the population into two strata based on gender. Then you use random sampling on each group, selecting 80 women and 20 men, which gives you a representative sample of 100 people.

Probability sampling methods _____________________ is similar to simple random sampling, but it is usually slightly easier to conduct. Every member of the population is listed with a number, but instead of randomly generating numbers, individuals are chosen at regular intervals.

Systematic sampling Example All employees of the company are listed in alphabetical order. From the first 10 numbers, you randomly select a starting point: number 6. From number 6 onwards, every 10th person on the list is selected (6, 16, 26, 36, and so on), and you end up with a sample of 100 people. If you use this technique, it is important to make sure that there is no hidden pattern in the list that might skew the sample. For example, if the HR database groups employees by team, and team members are listed in order of seniority, there is a risk that your interval might skip over people in junior roles, resulting in a sample that is skewed towards senior employees.

________________the group of individuals who will actually participate in the research.

The sample is the group of individuals who will actually participate in the research. When you conduct research about a groupn of people, it's rarely possible to collect data from every person in that group. Instead, you select a sample The population is the entire group that you want to draw conclusions about. The sample is the specific group of individuals that you will collect data from.

Non-probability sampling methods A _____________________ simply includes the individuals who happen to be most accessible to the researcher. This is an easy and inexpensive way to gather initial data, but there is no way to tell if the sample is representative of the population, so it can't produce generalizable results.

convenience sample Example You are researching opinions about student support services in your university, so after each of your classes, you ask your fellow students to complete a survey on the topic. This is a convenient way to gather data, but as you only surveyed students taking the same classes as you at the same level, the sample is not representative of all the students at your university.

Check pre test with an anova if there is a difference use a ____________________________ You do a study and find a significant difference in pretest what would you use

covariant and use an ANCOVA

In a _______________________, every member of the population has an equal chance of being selected. Your sampling frame should include the whole population. To conduct this type of sampling, you can use tools like random number generators or other techniques that are based entirely on chance. (YOU had this in INFORMATICS)

simple random sample Example You want to select a simple random sample of 100 employees of Company X. You assign a number to every employee in the company database from 1 to 1000, and use a random number generator to select 100 numbers.

Non-probability sampling methods If the population is hard to access, ________________________ can be used to recruit participants via other participants. The number of people you have access to "snowballs" as you get in contact with more people.

snowball sampling Example You are researching experiences of homelessness in your city. Since there is no list of all homeless people in the city, probability sampling isn't possible. You meet one person who agrees to participate in the research, and she puts you in contact with other homeless people that she knows in the area.