Y12 Research Methods

Extraneous Variables (EV’s) These are variables that might affect the DV if the experiment is not well controlled. Starter: A study aims to test the effects of different amounts of sleep deprivation (IV) on reaction time (DV). What else could affect reaction times making the results difficult to interpret?

Task 1; Identifying Extraneous Variables Look at the memory experiment on the handout. what are the EV’s that could affect the results of the experiment if they are not controlled? Task; For each of the flaws you have identified, say how the student could have controlled them

Eliminating EV’s - Standardised procedures Psychologists can eliminate confounding variables by using; STANDARDISED PROCEDURES – ensure all participants are tested in the same place at the same time of day, under the same conditions with the same equipment - STANDARDISED INSTRUCTIONS - Participants should be given the same instructions in exactly the same way

Standardised procedures include ; Briefing (informing participants why you are doing the experiment- ’My name is Debra Brooker and I am a Psychology student. I am going to conduct an experiment on memory. If at any time you wish to withdraw from the study then you are free to do so.....etc. ) Standardised Instructions (a step by step list of what you want the participants to do ‘ I am going to give you a list of words. Please look at the list for 20 seconds. Then give me the list back and write down on the paper provided as many words as you can remember ) Debriefing (informing participants what they have just done the experiment for ‘ Thankyou for taking part in my experiment. Is it Ok if I use your data in my experiment in the effect of music on learning. All data will be kept confidential and results will be available by contacting etc )

Plenary: Write down 1 extraneous variable AND 1 way of overcoming it that you have learned about today.

Imagine you have conducted a study that shows the behaviours performed by children in the playground at school. You want to plot a graph to show the number of times that boys and girls do the following; -Jump -Run -Skip -Fight How would you do it? STARTER

Analysis and Interpretation of data Which is which? - Bar chart – used to display data that is in categories - Histogram used to display data that is continuous - Frequency polygon or line graph- can show 2 or more distributions on one graph

Task; Practicing drawing graphs In each of the boxes provided (or on graph paper accurately if you prefer), draw a graph to represent the data given.

Plenary: Now answer the Past exam Question

What is meant by a correlation? Can you think of any examples of correlational data from studies we have looked at so far...? STARTERSTARTER

Analysis and interpretation of correlational data Correlations can either be positive or negative or show no correlation The stronger the correlation, the nearer it is to +1 or -1. If a correlation value (coefficient) = 0, then there exists no correlation between 2 variables. Scattergrams are useful techniques to show at a glance how 2 variables are related. One variable is plotted on the x axis against the other on the y axis. However, a statistical test is used to calculate the correlation coefficient in order to determine the exact nature of the correlation – IT’S SIZE AND DIRECTION!

What type of correlation?

Task: Sketch an example of each type of correlation: +ve, -ve and no correlation. Think of your OWN variables for each axis.

Measures of central Tendency & Dispersion Starter: Look at the 2 samples of data Condition A: Time taken to solve the puzzle with an audience (seconds) 23, 19, 24, 47, 23, 20 Condition B: Time taken to solve the puzzle without an audience (seconds) 45, 44, 43, 44, 46, 48 What do you notice from the data collected? How could you analyse the data so that any patterns could be seen? Condition A: Time taken to solve the puzzle with an audience (seconds) 23, 19, 24, 47, 23, 20 Condition B: Time taken to solve the puzzle without an audience (seconds) 45, 44, 43, 44, 46, 48 What do you notice from the data collected? How could you analyse the data so that any patterns could be seen?

Descriptive Statistics Descriptive Statistics allow you to describe the raw data you have collected and reduce them to just a few numbers that are easier to manage. There are 2 main types of calculations; Measures of Central Tendency- sometimes referred to as averages- a score that represents or is typical of the rest of the scores Measures of Dispersion- They tell us about the spread of scores or how spread out they are. Whenever you give a measure of central tendency, you should always give a measure of dispersion as well.

Measures of Central Tendency We can summarise data in a variety of ways, in order to identify patterns in it. Mean ‘Adding all the values (numbers) together in a set of scores, and then dividing the total by the number of values in a set’ Work out the mean from the following set of data 8, 12, 16, 17, 23, 24

Continued.... Mode....This is the most frequently occurring value in a set of scores. Sometimes there is no mode and sometimes there is more than one mode What is the mode in the 2 examples below? A: 23, 19, 24, 47, 23, 20, 23 B: 45, 44, 43, 44, 46, 48, 43 Mode....This is the most frequently occurring value in a set of scores. Sometimes there is no mode and sometimes there is more than one mode What is the mode in the 2 examples below? A: 23, 19, 24, 47, 23, 20, 23 B: 45, 44, 43, 44, 46, 48, 43

Continued... Median... The middle value in a set of scores.... You first must put all the values in order from lowest to highest. Then you must find the middle value. If there is no middle value, then you must find the midpoint of the 2 middle values What is the median of the following 2 sets of data: A: 3,3,4,6,7,9,9,11,13,15,16,18, 18 B: 15,17,17,18,19,20,22,22,22,26 Median... The middle value in a set of scores.... You first must put all the values in order from lowest to highest. Then you must find the middle value. If there is no middle value, then you must find the midpoint of the 2 middle values What is the median of the following 2 sets of data: A: 3,3,4,6,7,9,9,11,13,15,16,18, 18 B: 15,17,17,18,19,20,22,22,22,26

Measures of Dispersion Range... This is the numerical difference between the lowest and highest value in a set of scores Look at these 2 sets of data.... 3,5,8,8,9,10,12,12,13,15 mean=9.5 range =12 (3-15) 1,5,8,8,9,19,11,12,12,20 mean=9.5 range=19 (1-20) Both sets of data have the same mean but by knowing the range we can see that the spread of scores is quite different, which can be useful to know. Range... This is the numerical difference between the lowest and highest value in a set of scores Look at these 2 sets of data.... 3,5,8,8,9,10,12,12,13,15 mean=9.5 range =12 (3-15) 1,5,8,8,9,19,11,12,12,20 mean=9.5 range=19 (1-20) Both sets of data have the same mean but by knowing the range we can see that the spread of scores is quite different, which can be useful to know.

Standard Deviation This is a measure of the amount of variation from the mean within a set of data. The larger the standard deviation, the wider the spread of scores. Note: you do not need to calculate the range or standard deviation in the exam, just be able to say which is appropriate to use and when. This means knowing the advantages and disadvantages of each one. This is a measure of the amount of variation from the mean within a set of data. The larger the standard deviation, the wider the spread of scores. Note: you do not need to calculate the range or standard deviation in the exam, just be able to say which is appropriate to use and when. This means knowing the advantages and disadvantages of each one.

When using a....Use a... MeanStandard Deviation Median Range Mode Range Which ones to use together; RULE OF THUMB

Task: Using the textbook, complete the table giving a strength and a weakness of each of the measures of central tendency and each of the measures of dispersion. MeasureStrengthWeakness Mean Mode Median Standard deviation Range

Plenary: Who am I? When it is your turn read out a fact about one of the measures. Class have to identify which of the 5 measures is being referred to. Mean Mode Median Range Standard Deviation When it is your turn read out a fact about one of the measures. Class have to identify which of the 5 measures is being referred to. Mean Mode Median Range Standard Deviation

TASK: Complete the Research Methods questions no.3.8 on p.80 of the text book.