A standardized math test was administered to two groups of 5th graders, one group sampled from classes whose teachers had followed the existing curriculum and one group sampled from classes whose teachers had followed a new curriculum, and the scores were compared using a t-test with the following results: t-test: Two-Sample Assuming Equal Variances Old Curriculum New Curriculum Mean 75.31914894 65.65957447 Variance 118.613321 801.1424607 Obervations 47 47 Hypothesized Mean Difference 0 df 92 t Stat 2.183587807 P(T<=t) one-tail 0.015768226 t Critical one-tail 1.661585397 P(T<=t) two-tail 0.031536452 t Critical two-tail 1.986086317 You decide to use the conventional p=.05 as your cutoff for statistical significance. What do you conclude from this analysis? The wrong t-test was conducted because of the relative sizes of the two groups' variances. We cannot be sufficiently confident that there is a relationship between the math curriculum followed and students' test scores. There probably is a relationship between the math curriculum followed and students' test scores.
A standardized math test was administered to two groups of 5th graders, one group sampled from classes whose teachers had followed the existing curriculum and one group sampled from classes whose teachers had followed a new curriculum, and the scores were compared using a t-test with the following results: t-test: Two-Sample Assuming Equal Variances
Old Curriculum New Curriculum
Mean 75.31914894 65.65957447
Variance 118.613321 801.1424607
Obervations 47 47
Hypothesized Mean Difference 0
df 92
t Stat 2.183587807
P(T<=t) one-tail 0.015768226
t Critical one-tail 1.661585397
P(T<=t) two-tail 0.031536452
t Critical two-tail 1.986086317
You decide to use the conventional p=.05 as your cutoff for statistical significance. What do you conclude from this analysis?
- The wrong t-test was conducted because of the relative sizes of the two groups' variances.
- We cannot be sufficiently confident that there is a relationship between the math curriculum followed and students' test scores.
- There probably is a relationship between the math curriculum followed and students' test scores.
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