Some outcomes are categorical and contain many zeros (e.g. HTKS contains 102/218 zeros), thus we use zero-inflated model to fit them: Firstly, we use a binary model to fit “zero or not”, secondly we use poisson / quasi poisson model to fit the distribution.
And the interpretation of model can be: In the first step, binary model can represent “whether the children understand the game”, if he/she understood, then score is likely to be non-zero, otherwise zero; then in the second step, the poisson model can estimate the ability of children in this area / outcome.
Linear mixed longitudinal model is used.
Treatment is significantly positive (Estimate = 0.941, p value = 0.038), i.e. receiving treatment will increase the probability of achieving non-zero score or “understanding the HTKS game”.
Other covariates are not significant.
Baseline age (the age when children join the experiment) is significantly positive (Estimate = 0.102, p value = 0.004): older children are more likely to behave better. We are using linear term because no significant non-linear trend is discovered yet.
Sex & Time interaction is significantly positive (Estimate = 0.625, p value = 0.008): girls’ time effect is stronger than boys’. Here the time effect means their changed ability from time point 1 to time point 2, due to children are getting older.
Baseline age & Treatment interaction is significantly negative (Estimate = -0.122, p value = 0) : the baseline age will influence the effect of treatment. In the sense of average, children with baseline age smaller than 55 months have positive treatment effect, while those with baseline age bigger than 55 months have negative treatment effects.
Time effect is significantly positive (Estimate = 1.246, p value = 0.031), i.e. Compared with period 1, the period 2’s children have greater probability of achieving non-zero score or “understanding the HTKS game”.
Other covariates are not significant.
Covariates are not significant.
Time effect is significantly positive (Estimate = 1.266, p value = 0.028), i.e. Compared with period 1, the period 2’s children have greater probability of achieving non-zero score or “understanding the HTKS game”.
Other covariates are not significant.
Covariates are not significant.
Time effect is significantly positive (Estimate = 1.629, p value = 0.001), i.e. Compared with period 1, the period 2’s children have greater probability of achieving non-zero score or “understanding the HTKS game”.
Other covariates are not significant.
Sex effect is significantly positive (Estimate = 0.366, p value = 0.002): Girls are more likely to behave better.
No significant result.
There is significant difference between grils and boys about the time effecet (Estimate = 0.437, p value = 0) and treatment effect (Estimate = -0.374, p value = 0.011).
Time effect is significant (Estimate = 0.22, p value = 0.023).
Treatment effect is not significant (Estimate = -0.1, p value = 0.399).
Time effect is significant (Estimate = -0.217, p value = 0.003).
Treatment effect is significant (Estimate = 0.275, p value = 0.002).
There is significant difference between grils and boys about the time effecet (Estimate = -0.397, p value = 0) and treatment effect (Estimate = 0.342, p value = 0.012).
Time effect is significant (Estimate = -0.283, p value = 0.001).
Treatment effect is significant (Estimate = 0.221, p value = 0.043).
Time effect is not significant (Estimate = 0.114, p value = 0.082).
Treatment effect is not significant (Estimate = -0.121, p value = 0.132).
## table of HTKS (using paired data only, removing missing data):
##
## 0 1 2 3 4 5 6 7 8 10 11 12 13 14 16 17 18 19 20 21 22 23 26 27 29 30
## 95 6 20 5 6 1 3 1 8 4 1 4 2 7 4 2 2 2 3 2 4 1 1 1 2 2
## 31 32 34 37 38 40 43 46 47 48 52
## 1 1 2 3 1 2 2 1 2 1 1
| X | Estimate | Std..Error | z.value | Pr…z.. |
|---|---|---|---|---|
| (Intercept) | 1.8513063 | 0.1799857 | 10.2858543 | 0.0000000 |
| age | 0.1020116 | 0.0350805 | 2.9079258 | 0.0036383 |
| Receive_Treatment1 | 0.0540590 | 0.1813452 | 0.2980998 | 0.7656270 |
| as.factor(Sex)2 | 0.5022247 | 0.2750358 | 1.8260340 | 0.0678451 |
| as.factor(Time)2 | 0.1391914 | 0.1557823 | 0.8934995 | 0.3715897 |
| age:Receive_Treatment1 | -0.1219787 | 0.0204133 | -5.9754474 | 0.0000000 |
| Receive_Treatment1:as.factor(Sex)2 | -0.3853183 | 0.2666780 | -1.4448823 | 0.1484910 |
| as.factor(Sex)2:as.factor(Time)2 | 0.6248874 | 0.2372206 | 2.6342035 | 0.0084335 |
| X | Estimate | Std..Error | z.value | Pr…z.. |
|---|---|---|---|---|
| (Intercept) | -0.0281903 | 0.2551570 | -0.1104822 | 0.9120269 |
| age | 0.0246011 | 0.0465180 | 0.5288501 | 0.5969094 |
| as.factor(Sex)2 | 0.4917799 | 0.3313476 | 1.4841813 | 0.1377608 |
| Receive_Treatment1 | -0.9408508 | 0.4546022 | -2.0696134 | 0.0384886 |
| as.factor(Time)2 | -0.1326474 | 0.3983418 | -0.3329989 | 0.7391351 |
| X | Estimate | Std..Error | z.value | Pr…z.. |
|---|---|---|---|---|
| (Intercept) | 1.2489534 | 0.0944058 | 13.2296257 | 0.0000000 |
| age | -0.0093135 | 0.0139759 | -0.6663966 | 0.5051577 |
| Receive_Treatment1 | 0.0451497 | 0.1240892 | 0.3638489 | 0.7159709 |
| as.factor(Sex)2 | -0.0588649 | 0.1021747 | -0.5761200 | 0.5645341 |
| as.factor(Time)2 | 0.2198879 | 0.1232909 | 1.7834885 | 0.0745068 |
| X | Estimate | Std..Error | z.value | Pr…z.. |
|---|---|---|---|---|
| (Intercept) | 0.2637709 | 0.3999526 | 0.6595053 | 0.5095713 |
| age | 0.0434761 | 0.0807657 | 0.5382988 | 0.5903708 |
| Receive_Treatment1 | 0.5494247 | 0.6401436 | 0.8582836 | 0.3907359 |
| as.factor(Sex)2 | -0.0330561 | 0.5591436 | -0.0591191 | 0.9528572 |
| as.factor(Time)2 | -1.2455259 | 0.5764964 | -2.1605092 | 0.0307333 |
| X | Estimate | Std..Error | z.value | Pr…z.. |
|---|---|---|---|---|
| (Intercept) | 1.3843870 | 0.0943798 | 14.6682542 | 0.0000000 |
| age | -0.0096918 | 0.0146161 | -0.6630945 | 0.5072701 |
| Receive_Treatment1 | 0.0642115 | 0.1239128 | 0.5181992 | 0.6043193 |
| as.factor(Sex)2 | -0.0690907 | 0.1068597 | -0.6465549 | 0.5179201 |
| as.factor(Time)2 | 0.1983791 | 0.1193676 | 1.6619173 | 0.0965293 |
| X | Estimate | Std..Error | z.value | Pr…z.. |
|---|---|---|---|---|
| (Intercept) | 0.2814417 | 0.4006534 | 0.7024568 | 0.4823943 |
| age | 0.0435913 | 0.0811134 | 0.5374113 | 0.5909835 |
| Receive_Treatment1 | 0.5556033 | 0.6403152 | 0.8677029 | 0.3855570 |
| as.factor(Sex)2 | -0.0282149 | 0.5610975 | -0.0502853 | 0.9598951 |
| as.factor(Time)2 | -1.2656109 | 0.5760034 | -2.1972281 | 0.0280042 |
| X | Estimate | Std..Error | z.value | Pr…z.. |
|---|---|---|---|---|
| (Intercept) | 1.5031960 | 0.1031532 | 14.5724597 | 0.0000000 |
| age | 0.0311040 | 0.0237259 | 1.3109743 | 0.1898665 |
| I(age^2) | 0.0007670 | 0.0043826 | 0.1750061 | 0.8610748 |
| Receive_Treatment1 | 0.0249326 | 0.1202171 | 0.2073966 | 0.8357001 |
| as.factor(Sex)2 | 0.3663824 | 0.1165387 | 3.1438680 | 0.0016673 |
| as.factor(Time)2 | 0.1580867 | 0.1161112 | 1.3615119 | 0.1733520 |
| X | Estimate | Std..Error | z.value | Pr…z.. |
|---|---|---|---|---|
| (Intercept) | 0.3909464 | 0.2748835 | 1.4222254 | 0.1549608 |
| age | -0.0320729 | 0.0736718 | -0.4353478 | 0.6633100 |
| I(age^2) | -0.0200076 | 0.0147120 | -1.3599486 | 0.1738462 |
| Receive_Treatment1 | 0.2354658 | 0.4889672 | 0.4815575 | 0.6301204 |
| as.factor(Sex)2 | 0.6054718 | 0.3384683 | 1.7888581 | 0.0736377 |
| as.factor(Time)2 | -1.6292918 | 0.4684072 | -3.4783664 | 0.0005045 |
| X | Estimate | Std..Error | t.value |
|---|---|---|---|
| (Intercept) | 2.1165913 | 0.5200362 | 4.0700847 |
| age | 0.0066965 | 0.0096694 | 0.6925412 |
| as.factor(Sex)2 | 0.1339700 | 0.0680292 | 1.9693003 |
| as.factor(Time)2 | -0.1057525 | 0.0865136 | -1.2223805 |
| Receive_Treatment | 0.0965722 | 0.0943254 | 1.0238198 |
| X | Estimate | Std..Error | t.value | p.value |
|---|---|---|---|---|
| (Intercept) | 3.5364024 | 0.0691638 | 51.1307942 | 0.000 |
| as.factor(Sex)1 | -0.0712329 | 0.0855110 | -0.8330265 | 0.405 |
| as.factor(Time)2 | 0.2199753 | 0.0965549 | 2.2782401 | 0.023 |
| Receive_Treatment1 | -0.0997384 | 0.1183119 | -0.8430120 | 0.399 |
| as.factor(Sex)1:as.factor(Time)2 | -0.4367405 | 0.1210499 | -3.6079385 | 0.000 |
| as.factor(Sex)1:Receive_Treatment1 | 0.3744700 | 0.1470945 | 2.5457781 | 0.011 |
| X | Estimate | Std..Error | t.value | p.value |
|---|---|---|---|---|
| (Intercept) | 3.4651695 | 0.0502841 | 68.9117849 | 0.000 |
| Sex2 | 0.0712329 | 0.0855110 | 0.8330265 | 0.405 |
| as.factor(Time)2 | -0.2167652 | 0.0730084 | -2.9690465 | 0.003 |
| Receive_Treatment1 | 0.2747316 | 0.0874018 | 3.1433156 | 0.002 |
| Sex2:as.factor(Time)2 | 0.4367405 | 0.1210499 | 3.6079385 | 0.000 |
| Sex2:Receive_Treatment1 | -0.3744700 | 0.1470945 | -2.5457781 | 0.011 |
| X | Estimate | Std..Error | t.value | p.value |
|---|---|---|---|---|
| (Intercept) | 1.5298212 | 0.0589436 | 25.953991 | 0.000 |
| as.factor(Sex)2 | -0.1159690 | 0.1002369 | -1.156950 | 0.247 |
| as.factor(Time)2 | 0.1138711 | 0.0654308 | 1.740330 | 0.082 |
| Receive_Treatment1 | -0.1211462 | 0.0804392 | -1.506059 | 0.132 |
| as.factor(Sex)2:as.factor(Time)2 | -0.3972181 | 0.1083321 | -3.666670 | 0.000 |
| as.factor(Sex)2:Receive_Treatment1 | 0.3418826 | 0.1353766 | 2.525419 | 0.012 |
| X | Estimate | Std..Error | t.value | p.value |
|---|---|---|---|---|
| (Intercept) | 1.4138522 | 0.0810746 | 17.438909 | 0.000 |
| Sex1 | 0.1159690 | 0.1002369 | 1.156950 | 0.247 |
| as.factor(Time)2 | -0.2833469 | 0.0863404 | -3.281743 | 0.001 |
| Receive_Treatment1 | 0.2207364 | 0.1088869 | 2.027208 | 0.043 |
| Sex1:as.factor(Time)2 | 0.3972181 | 0.1083321 | 3.666670 | 0.000 |
| Sex1:Receive_Treatment1 | -0.3418826 | 0.1353766 | -2.525419 | 0.012 |