sales than stores in other conditions Reason rejecting the null simply means

# Sales than stores in other conditions reason

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sales than stores in other conditionsReason: rejecting the null simply means that at least the average for one group is different from others, but didn’t say which group42Tests of Differences 1. One Sample 2. Two Independent Samples 3. Paired Samples 4. More Than Two Samples Which t test to use? It depends on (1). the number of variables and (2). Number of groups involved t tests ANOVA 43
15 One-Sample t-test One sample Independent Samples t-test Two independent samples Paired samples t-test Two dependent samples ANOVA Two or more samples Summary Average temperature in August = 17 ° Sales in store A = Sales in store B Knowledge of statistics after class = before class Average fuel prices in suburbs A,B and C are different 44 Today’s agenda 45 Hypothesis testing – tests of differences Different types of t tests Two-tailed vs. one-tailed test – ANOVA How to write about hypothesis testing A few words on assignment 2 How to write about hypothesis testing – the formulaic approach • 1 st step – describe the test – Which test did you use? – What variables are involved? What are the groups involved? • 2 nd step – describe the test results – What did you conclude (reject or not reject the null)? What is the p value? – What does it mean in plain English? 46
16 A (type of t test) _____ was conducted to compare the difference between (group or variable 1) _____ and (group or variable 2) _____ in/for (variable or group name) _____. in our case this is as follows: An independent samples t test was conducted to compare the difference between teenagers and adults in their mean preference before entering the theme park. Or A paired sample t test was conducted to compare the mean preference before and after visiting the theme park Describing the test - t test 47 A one-way between subjects ANOVA was conducted to compare the effect of (IV) _____ on (DV) _____. in our case this is as follows: A one-way between subjects ANOVA was conducted to compare the effect of different promotion programs on average store sales. Describing the test – one way ANOVA 48 There was a significant (or not a significant) difference in (variable(s)) _____ between (groups) _____ at the p<.05 level [p = ____]. (group 1) _____ exhibit higher (or lower) (variable name) _____ than (group 2) _____ . in our case this is as follows: The null hypothesis is rejected. There is a significant difference in preference before entering the park between teenagers and adults [p = .006]. Teenagers exhibit higher average preference before entering the park than adults. (copy/paste the SPSS output tables here) Describing the results – t test 49
17 There was a significant (not a significant) effect of IV _____ on DV _____ at the p<.05 level for (the number of) _____ conditions [p = ____]. in our case this is as follows: The null hypothesis is rejected. There is a significant effect of promotion on store sales at the p<.05 level for the three conditions [p = .001]. (copy/paste the SPSS output tables here) Describing the results – one way ANOVA 50 Today’s agenda 51 Hypothesis testing – tests of differences Different types of t tests Two-tailed vs. one-tailed test – ANOVA How to write about hypothesis testing A few words on assignment 2 What is expected of the assignment?

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• Statistics, Null hypothesis, Statistical hypothesis testing, Statistical tests, Student's t-test