REVIEW for Exam 2. Chapters 9 13 (& chi-square in ch8)

Transcription

1 REVIEW for Exam Chapter 9 3 & chi-quare in ch8

2 True or Fale. Etimated tandard error of the mean in a paired-ample t-tet i baed on the variance of the difference core.. W/in S deign i particularly ueful for reearch quetion concerning change over time. 3. One diadvantage of a w/in S deign i that it require more ubject compared to an between-s deign. 4. A general concern for reearcher i that participant in one condition will be different from participant in another condition, but thi i not a problem for within-ubject deign. 5. The ample mean or difference core i alway ued a a point etimate of the population mean or mean difference. 6. Holding everything ele contant, the width of the confidence interval will increae a the tandard error decreae. 7. If a 95% confidence interval for the difference between two treatment mean extend from -.5 to +5.0, then you can conclude that there i no ignificant difference between the treatment. 8. In an ANOVA, variance i partitioned into between treatment and within treatment variance. 9. In an ANOVA, S total will alway equal the um of S between and S within.

3 True or Fale. The alternative hypothei for ANOVA i that the mean of the condition or group are equal.. In general, for a large F-ratio you will likely not reject the null hypothei. 3. The larger the mean difference between treatment the larger the S within. 4. After conducting a -way ANOVA pot-hoc tet are needed if the null hypothei i rejected. 5. Rather than multiple t-tet, pot-hoc tet are ued to reduce Type I error. For a w/in S deign, the difference between condition can be due to treatment effect or error, but not due to individual difference. 6. One major difference between one-way and repeated ANOVA i that SS total i calculated differently. 7. When individual difference are large, a w/in S deign may detect a treatment effect more eaily than an independent meaure deign. 8. A repeated-meaure ANOVA tated, F4, 0 =.7, p <.0. The tudy had four treatment condition. 9. For a within-ubject deign, it i more appropriate to ue a repeated ANOVA than a paired-ample t-tet when there are two level of the factor. 3

4 Practice quetion According to the US Bureau of the Cenu, 75% of adult regularly drank alcohol in 985. A reearcher predict that fewer adult drink now compared to then. A ample of 00 adult i aked about their current drinking habit and 67 report drinking and 33 report not drinking. Calculate the X chi quare. f o f e x What are the df? f e What i the X cv? What concluion hould be drawn? 4

5 Practice quetion. A health magazine recently reported a tudy in which reearcher claim that iron upplement increae memory and problem-olving abilitie in a random ample of college women. All the women took memory and problem-olving tet at the beginning of the tudy, then took iron upplement, and then took the ame tet again at the end of the tudy. What i wrong with thi deign? What confound could be leading to the reult of the improved memory and problem-olving kill?. In a tudy of effect of exercie on tre meaured a heart rate, participant are randomly aigned to either the no exercie, low intenity exercie, moderate intenity exercie or extreme intenity exercie group. Identify what type of deign i ued. What i the IV? How many level doe it have? What are the control veru experimental group? What i the V? What tatitic hould be ued? 5

6 Practice quetion. What i the relationhip between external validity and the college ophomore problem?. Identify the two type of correlated-group deign. Explain each one. 3. What i counterbalancing and how i it achieved? What i a latin quare? 4. A college tudent i intereted in whether there i a difference between male and female tudent in the amount of time pent tudying each week. The tudent gather information from a random ample of 7 male = 9.86, = 3.8 and 7 female = 4.9, =.56 tudent on campu. The number of hour tudying i normally ditributed.. What tatitic hould be ued to analyze the data?. What are the null and alternative hypothee? 3. Calculate the tatitic. 4. What are the df? What i the critical value? What hould the reearcher conclude? Write up the reult. 5. If ignificant, compute the effect ize and interpret it. 6

7 Practice quetion A pychologit hypotheize that people are more likely to help an older woman in trouble compared to a young man. A reearcher i intereted in examining the effect of volunteering for community ervice on elf-eteem.. How would you conduct a tudy that ue a betweenubject deign?. What i the IV and how many level?. What i the V? 3. What tatitic would you ue?. How would you conduct a tudy that ue a withinubject deign?. What i the IV and how many level?. What i the V? 3. What tatitic would you ue? 7

8 Practice quetion. Explain when it would be appropriate to ue a t-tet veru a one-way ANOVA.. Explain what between-group variance and within-group variance are compried of. 3. When and why i it neceary to ue pot-hoc tet? 4. An experiment on pizza topping preference had n = 8 where each S rated cale 0-0 each type of pizza. The mean are below. Fill-in the ret of the ANOVA table. Plain = 8.5 Sauage = 6.8 Pepperoni = 6.5 Everything =.7 Source df SS S F p Between 50 Within Participant Error 50 Total Re-calculate S and F if it wa a between-s deign intead! 8

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10 Review t-tet Single-ample t-tet df = N Independent ample t-tet df = n +n Related or paired-ample t-tet df = N m t m m t t n N X S n n N N S n N X S

11 ANOVA formula One-way ANOVA df total = N df between = k df within = n or N k Two-way ANOVA df total = N df between = k or # cell - df within = N k or n- df A = k # row for factor A df B = k # column for factor B df AxB = df between df A - df B Repeated-meaure ANOVA df total = N df between = k df within = N k df between ubject = n df error = df within df between ubject One-way ANOVA S S between within F SS df S S SS df within between between within within between Repeated-meaure ANOVA SSbetween Sbetween df S F error S S SS df error between error error between

12 Effect ize analye z-tet CI = +/- z*σ One-ample t-tet CI = +/- t* Independent t-tet CI = +/- t* - Cohen d Small >. edium >.5 Large >.8 Variance accounted for r Small >.0 edium >.09 Large >.5 t r t df Paired ample t-tet CI = ± t* Cohen d d Variance accounted for r d ANOVA: effect ize = eta SS SS Between Total

13 Other formula Goodne of fit chi-quare Frequency table of data Oberved frequencie f o Compare to null hypothei Expected frequencie f e Expected frequency f e = pn Chi-quare equation f o f e x f df = C, where C = # of categorie e r z x X Y XY N X Y X Y N N