Jacklyn Giampa Research Methods 241 Lecture 6 2 4 16 Example 3 Participants sat and watched advertisements on the screen two types of ads food non food then were asked to recall 40 students all fasting for 8 hours no food half of the students saw ads without eating and the other half were given a meal of pasta with sauce before seeing the ads Hypothesis motivation and type of advertisement will affect recall of product names Iva motivation hungry satiated IVb type of ad food non food DV Number of product names recalled What type of design is this 2 way 2x2 mixed design 2 independent variables 2 IVs with 2 types of ad each subject experiences their own hunger satisfaction and then saw both types of ads repeated measures food Non food Means motivation hungry 18 8 18 8 2 13 Satiated 12 8 12 8 2 10 Means type of ad 18 12 2 15 8 1 2 3 Is there a main effect of motivation yes as the means of motivation numbers are different This tells us that hungry people remembered more food ads than those who were fed before participating Is there a mean effect of type of ad yes an average of 15 people remembered the food ad and an average of 8 for the non food ad More food ads were recalled than non food ads Is there an interaction of motivation of type of ads yes because the graph is not parallel we can see that YES there is an interaction For food ads hungry people recalled more than satiated people For non food ads people recalled the same number of ads in both hungry and satiated groups regardless of motivation any time they are not parallel there is an interaction You could draw another graph for this example that would be just as appropriate For this graph you are simply switching the variables so that food versus non food is on the x axis and the mean of ads recalled is on the y axis This graph better shows the drop in the food ads recalled by hungry versus satiated Exam Five multiple choice questions Then the rest is short answer and problem solving There is a sample of exams in the course packet Example 4 Hypothesis lack of sleep and problem difficulty will affect ability to solve problems IVa hours of sleep 4hrs 8hrs IVb problem difficulty 3 stage easy 6 stage hard DV of problems solved in 1 hour 40 participants brought into the lab half allowed to sleep for a full 8 hours other half only 4 fours Then all participants are given a set of math problems to solve For the 20 people who slept 8 hours 10 would be given easy 10 would be given hard Same with the four hours of sleep half saw the easy half saw the hard What kind of problem is this 2 way 2x2 between subjects 2IVs 2 ways for each IV hours of sleep 2 types of problems easy or hard 4 h sleep 8 h sleep 3 stage prob 6 stage prob Means sleep 20 10 20 10 2 15 20 10 20 10 2 15 Means problem difficulty 20 20 2 20 10 10 2 10 1 2 3 Is there a main effect of sleep comparing the means did it make any difference No there is no main effect Is there a main effect of style of problem difficulty comparing the means of problem difficulty yes there is a difference Three stage problems you could get through 20 problems and with the six stage problems people solved on average only 10 People solved more easy problems than hard problems Is there an interaction draw your graph using interior numbers as always 20 20 10 10 Since the lines are extremely parallel there is evidently NO INTERACTION The effect on hours of sleep is exactly the same for both easy and hard problems But we can make another graph switching the variables on the x and y axis however this one also comes out parallel with no interaction as well Example 5 Hypothesis age of children and type of noun will affect recall IVa age 7 10yrs IVb noun type abstract concrete DV of nouns correctly recalled 20 children 20 words half or the words were abstract half were concrete randomly arranged on a list What type of design is this 2 way 2x2 mixed design 2 IVs 2 ways for IV 7yrs or 10 yrs Mixed because age is between subjects and type of noun is repeated measure Abstract Concrete Mean age of child 7y o 1 5 6 2 3 10y o 4 8 12 2 6 Mean type of noun 2 5 6 5 1 2 3 Is there a main effect of age yes ten year olds recall more than seven year olds Is there a main effect of type of noun yes the concrete nouns were easier to recall than the abstract nouns Is there an interaction Again 2 graphs to draw arbitrary which one we decide The interaction graph showed that the lines were parallel thus showing that there is NO INTERACTION