LitCovid-sentences  

PMC:7547912 / 21139-23943 JSONTXT 8 Projects

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Id Subject Object Predicate Lexical cue
T129 0-51 Sentence denotes Inferential t-statistic (Welch’s two-sample t test)
T130 52-224 Sentence denotes In the present study, the significant impact of COVID-19 pandemic confinement on air quality in studied locations was determined by right-tailed, Welch’s two-sample t test.
T131 225-402 Sentence denotes The complete data set was divided into two groups, pre-confinement (A) and during confinement (B) to assess if there is a statistically significant effect of confinement on AQI.
T132 403-549 Sentence denotes Independent random samples of sizes n1, n2 were drawn by using a random number table from both the groups and applied t test using the R-software.
T133 550-622 Sentence denotes This inferential statistic was used to test the following hypothesis:H0:
T134 623-759 Sentence denotes No significant difference between the means of two groups i.e., no significant effect of COVID-19 pandemic confinement on AQI (μ1 = μ2).
T135 760-763 Sentence denotes HA:
T136 764-970 Sentence denotes Significant difference between the means of two groups i.e., air quality is significantly improved during COVID-19 pandemic confinement (μ1 > μ2), where μ1 and μ2 are the population means of the two groups.
T137 971-1202 Sentence denotes From Table 2, we can observe that the t-statistic (5.91), which when compared with critical t value (1.67) at 5% level of significance (α), rejected the null hypothesis and confirmed the significant reduction in the AQI for site 1.
T138 1203-1316 Sentence denotes The p value was also found to be very small, suggesting that the COVID-19 pandemic confinement reduced AQI (45%).
T139 1317-1466 Sentence denotes The p value revealed it is “unlikely” that we would observe such an extreme test statistic t* in the direction of HA if the null hypothesis was true.
T140 1467-1552 Sentence denotes Therefore, the initial assumption that the null hypothesis is true must be incorrect.
T141 1553-1716 Sentence denotes That is, since the p value, 0.00000015, is very less than α = 0.05, we reject the null hypothesis H0 : μ1 = μ2 in favor of the alternative hypothesis HA : μ1 > μ2.
T142 1717-1867 Sentence denotes However, if we lowered our willingness to make a type I error to α = 0.01 instead, the significant rejection of the null hypothesis is again observed.
T143 1868-2004 Sentence denotes This is due to reduction in anthropogenic activities including fuel and coal burning, vehicular emissions, and manufacturing industries.
T144 2005-2047 Sentence denotes Table 2 Welch’s two-sample t test analysis
T145 2048-2075 Sentence denotes Site 1 Site 2 Site 3 Site 4
T146 2076-2147 Sentence denotes Sample A Sample B Sample A Sample B Sample A Sample B Sample A Sample B
T147 2148-2204 Sentence denotes Mean 241.65 134.25 159.12 65.77 144.86 57.45 75.78 63.20
T148 2205-2241 Sentence denotes Observations 36 35 36 35 36 35 36 35
T149 2242-2278 Sentence denotes Hypothesized mean difference 0 0 0 0
T150 2279-2308 Sentence denotes Degree of freedom 62 38 40 42
T151 2309-2394 Sentence denotes 95% confidence interval (71.05, 143.75) (69.45, 116.99) (63.14, 111.65) (1.09, 24.05)
T152 2395-2426 Sentence denotes t-statistic 5.91 7.94 7.28 2.20
T153 2427-2486 Sentence denotes P (T ≤t) one-tail 0.00000015 0.0000000014 0.0000000074 0.03
T154 2487-2526 Sentence denotes t Critical one-tail 1.67 1.68 1.68 1.68
T155 2527-2804 Sentence denotes The same behavior can be observed from the data of Table 2 for 2nd, 3rd, and 4th studied locations where the much lowered p values exhibited the statistically significant effect of COVID-19 pandemic confinement in lowering the sample mean AQI by 58%, 60%, and 17% respectively.